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Understanding Your

Low Energy Building and

How to Get the Best Value for Money when constructing your project

Source: Euractive.com

Essential guidance for reading and understanding your bespoke estimate

The Low Energy Buildings you’ve always wanted

…adding value to sustainability

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Whatever your project … … we can help you build it better. Whatever you build will represent a huge investment of

time, money and energy. Naturally you want to achieve

this as quickly and cost effectively as possible and create

a sound, secure investment.

Timber based structures are increasingly recognised as

one of the best ways of doing this. They provide very

long lasting, highly durable, super energy-efficient, envi-

ronmentally friendly and sustainable buildings. In fact some of the oldest structures in the world still

in use today are based on timber; from 7th Century Japanese temples, through medieval ‘Black &

White’ in the UK & Europe, to iconic modern homes in most countries.

Timber frame building methods account for over 70% of new homes in Australia and North America,

and up to 90% in Scandinavia. When fabricated in a dry factory environment they are very accurate,

save on waste, and are quick and relatively

easy to assemble on site. They can be erected

under most climatic conditions, and provide a

closed ‘weatherproof’ shell that can be com-

pleted inside while waiting for the weather to

improve outside. Far more resilient and safe in

earthquake and hurricane conditions, it is actu-

ally the timber frame that stops any external

brickwork skin from falling down. Bricks can of

course be replaced with tiles, brick slips, ren-

der, timber and many other forms of external

cladding that may need less costly foundations.

Perhaps most important of all, they deliver highly energy efficient, supremely comfortable homes

that are easy and economical to own, run and maintain.

These are just some of the reasons why we use them to Design & Build Low Energy Homes.

Specially developed to simplify ways of meeting the increasingly high demands of Building Regula-

tions and moves toward ‘No Central Heating” and “Passivhaus” performance standards, your esti-

mate sets out comparative prices for 5 levels of rationalised Timber Frame (TF) and Structural Insu-

lated Panel (SIP) Frame performance.

To help you in your quest to build quickly, economically and efficiently, it also gives you a set of ‘pick

and mix’ options enabling you to create your own specifications as well as providing guidelines for a

range of full build cost methods.

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Timber Frame, SIP Frame, or CLT Frame – it’s your choice!

Structurally these two types of structure are fabricated and work quite differently:-

A Timber Frame is made of solid timber top, bottom, side and intermediate upright timbers.

These have a sheathing board (usually 9mm

OSB) fixed across the outside to ‘brace’ the

timbers against being pushed out of square and to

provide a barrier to the elements. The result is an

“Open Cell’ panel into which insulation can be

fitted, either in the factory or on site, to form

a warm wall.

These panels are then butted together,

nailed at the sides and along the bottom and

usually a solid ‘head binder’ timber fixed

across the tops. This keeps the panels straight and adds to the overall strength.

The loads from the upper floor/s and roof are carried by the timber uprights (studs) and

transmitted down to the founda-

tions. Depending on the panel de-

sign and thickness of insulation, a

‘service void’ may be left on the

inside into which wiring and pipe-

work can be fitted.

The inside face is then lined with

a Vapour Control Layer (VCL) to

prevent moisture

vapour getting into the ‘intersti-

tial’ area “between the inside

and outside and condensing into

water where the insulation is. An

internal lining, usually plaster-

board, is then fitted across the in-

side of the wall frame to create

the rooms inside.

A SIP (Structurally Insulated Panel) frame

is made by sandwiching a core of insulation

between two sheathing boards. Usually this

insulation is rigid foam made in one of two

ways

o a thick, pre-made sheet to which

the sheathing is firmly glued all

over

o a factory jig and press which sepa-

rates the two sheathing boards

while the insulation is injected into

the panels as a liquid which ex-

pands to fill all the space inside and

bond firmly to the whole of the inside faces.

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These panels have a ‘rebate’ cut into the core around the edges, either pre-formed during

fabrication, or cut out afterwards. This enables the panels to be slotted over a ‘sole plate’ at

floor level and either a solid timber, or a SIP spline, to be

slotted into the vertical junctions, and a ‘top plate’

dropped into the heads of the panels to keep them

straight and receive upper elements of the structure.

In this case the loads from the upper floors and roof are

carried by the whole panel, with the insulation core act-

ing to create a rigid framework. Openings for doors and

windows are cut out of the panels and rebates for lin-

ings formed, usually in the factory, with solid timber linings fitted around these openings to

which the doors and windows can subsequently be fixed.

The inside face may have a VCL fixed over it, as with the timber frame, before battens are

fixed to the inner sheathing to create a service void for pipes and wiring and to form a

framework for the inner (plasterboard) lining.

CLT (Cross Laminated Timber) Frame

Cross-laminated timber, known simply as CLT, is an engineered timber product in which small timber

sections are formed into large structural panels that are light, stable and very strong.

CLT has been around for several years, with most of the demand coming from the education market. Several fac-tors have come together to fuel the growth in the prod-uct’s use. A resurgent housing market is putting pres-sure on supplies of traditional materials and prompting developers to look for speedier alternatives - brick and block is slow and labour-intensive and it can be difficult to get hold of either of them. Consequently, housebuild-ers and developers are waking up to the fact they can get their building up and get their money back faster by using CLT.

These panels, which are available in a variety of sizes, are great for building entire structures, including inter-nal walls, floors and roofs, very quickly. As with Timber Frame & SIP Frame, the lightweight nature of the mate-rial means foundations can be smaller and cheaper, it is clean to use, with little waste, and it is made from read-ily available, renewable softwoods, which makes achiev-ing high BREEAM (BRE Environmental Assessment Method) ratings easier, and looks good in the corporate sustainability report.

The height of CLT buildings is creeping up. Buildings of 10 and more storeys have already been built using CLT, and up to 25 storeys are on the drawing board.

Which System is Right for me? Although it is not possible to advise on this without full drawings and many more details, the follow-ing general guideline may prove helpful:-

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Timber Frame - this panelised form of platform frame construction is the most basic and usually the least expensive of the three. The basic timber frame can be erected and closed in quickly. If roof sarking board, membrane, counter-batten and windows are fitted then you will have a (near) ‘wind and watertight’ shell. This can stand for several months while work continues on the inside before external cladding (e.g. brickwork, tile-hanging, cedar cladding, render), roof tiling, etc. needs to be fitted, although (subject to weather) these can proceed at the same time if you wish, reducing your overall build time.. Unless insulation is factory fitted to the walls to create ‘open SIP’ panels, you will have to do this on site. Likewise, unless an open or closed SIP roof is chosen, roof insulation always has to be fitted on site. The type and location of roof insulation is a particular consideration that needs attention, depending on design. Typically 120mm of rigid foam (PIR) insulation is factory fitted inside a 140mm frame, leav-ing a circa 20mm ‘service void’ before the VCL (Vapour Control Layer) and (plasterboard) internal lining are fitted. This reduces / avoids the need to batten out on the inside before internal linings are fitted. In their basic form, panelised Timber Frames can create shells with an airtightness of around 7 air changes per hour. They can be made very airtight, but if used for an extension this may not be very cost efficient. However, they are an excellent choice for extensions, where the existing structure may be quite ‘leaky’ and draughty.

SIP Frame – as the name (Structural Insulated Panels) states these panels are all produced with the insulation already in them. The value of this will depend on the overall thickness of the panel (we offer from 75mm to 250mm in 25mm increments). Due to the way they are joined together, when erected correctly they can provide quite high resistance to air leakage. In most cases they also offer a reduced incidence of thermal bridg-ing across the panels, although timber is in itself a very good insulator. However, where the structure needs to be strengthened by the addition of steel elements (which depends on the special structural engineering) this can become a problem. Like Timber Frame, the outside of the SIP Frame is usually wrapped with a ‘breather mem-brane’ to protect this from the weather. Unlike Timber Frame (unless fully filled) it will need battens to be fixed to the inside of the walls to create ‘service voids’ behind the internal lin-ings. SIP Panels can also be used for the roof structure, although these require quite specialised design and typically require a purlin running through the roof space (or rooms if there is any part of a room in the roof) to support them. This often results in ’down-stand’ beams need-ing to be featured inside the building. SIP Frames cost more than Timber Frames, but are ideal for uncomplicated new homes with straightforward roofs. If the ‘roof-scape’ is complex then it may be better to opt for a Tim-ber Frame solution, or SIP panel walls with a ‘cut’ roof that can more easily resolve the re-quired detailing.

CLT Frame – which is effectively engineered solid wood glulam– is overall more expensive than Timber Frame and SIP Frame. It can have internal channels for service ducts and can also have a finished surface that can be exposed as part of the décor. This can also apply to the floors, ceilings and roofs, with floor spans up to 8m being possible for the thickest mate-rial (we offer from 80mm to 249mm in 20mm increments, with 100mm being most common for walls).

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However, while a good natural insulator in itself, to meet Building Regulation requirements, CLT buildings will need to have additional insulation fitted, either inside or outside. It should also be noted that heavy water accumulation (e.g. rain or construction water) can cause an extreme increase in wood moisture content. In rare cases this may change the vol-ume of glulam elements, resulting in displacements and constraints in connected construc-tions. The elements must be protected from direct moisture penetration by covering films and any excess moisture must be reduced with air dehumidifiers. The structural design and engineering of CLT houses is significantly different from Timber Frame and SIP Frame structures, but it can be quick to erect, offer very ‘solid’, long lasting buildings and the ability for achieve low cost exposed timber surfaces. It can be readily used for small extensions, garden cabins, ‘granny annexes’, houses and flats up to 4 or 5 storeys and (subject to selection of material, design and engineering) for multi storey blocks much greater height.

Don’t forget the ‘hidden’ costs In addition to the cost guidelines provided, you may also have to meet architectural design costs and

local authority fees as well as pay for:-

Planning requirements

a site survey to establish the exact boundaries and position of new buildings. Sometimes

buying an Ordnance Survey map may be sufficient, but with a tight site a measured sur-

vey is recommended. Also include floor areas and heights of existing and new buildings.

a Design & Access statement (e.g. conformity with neighbourhood and highway safety)

an Environmental Impact Statement (e.g. avoidance of endangering flora and fauna)

Building Regulation requirements

Even if you don’t need planning permission, permanent buildings over 15m2 floor area will need:-

A SAP (Standard Assessment Procedure) cer-

tificate of the CO2 (and energy) performance

of your design.

This will take into consideration the effect of

surrounding buildings and trees, orientation

of the building, the amount of glazed and

other openings, how the building will be

heated, and so on.

A ground or soil survey to determine what

type and depth of foundations are required

and whether there are any hidden hazards,

like tree roots – or trees that have been re-

moved within the last few years which might affect the way the ground behaves – and

the ground water table.

Engineering calculations – we include these for the superstructure of our package kits

above ground level, BUT you will still need your foundations to be designed by a struc-

tural engineer who will provide calculations for your Building Regulation application.

Building Regulation approval, which may require an additional set of drawings showing

construction details, sections, foundations, drainage arrangements, proximity of build-

ings to trees and roots, etc.

an independent Building Inspector.

Many firms now offer this service, including the NHBC (National Home Builders Council)

and LABC (Local Authority Building Control). Both of these and some others also offer

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Building Warranty Insurance to complement their inspections. We are LABC Partners

which enables us to obtain prior acceptance for your Building Regulations via our local

LABC office. They then advise your local LABC office that everything is acceptable for

them to issue you with Building Regulation Approval.

to conform to the CDM Regulations by appointing someone as the “Principle Designer”

(this is not necessarily your architect) and a “Principle Contractor”. Their function is to

ensure that all the Health & Safety Regulations are observed and proper records kept.

Satisfying the Regulations Planning, Building and other regulations have become quite compli-

cated and are getting more so. It is, for example, quite possible to ob-

tain Planning Permission for a building but not be able to build it be-

cause it does not meet Building Regulation requirements.

To conform to EU regulations the UK Government has defined limits

on CO2 emissions of new buildings and extensions. Set out in Ap-

proved Document L of the Building Regulations (“Part L”1) these are

calculated by an assessor using a “Standard Assessment Procedure” –

the SAP Assessment2. This takes into account U-values3 (the energy-ef-

ficiency of fabric elements), airtightness, heating systems, renewable

energy and other factors. Whilst it is possible to reduce net emissions

by using renewable energy, Part L also requires a minimum Fabric En-

ergy Efficiency (FEE), which is determined purely by the building enve-

lope.

The recent inclusion of FEE in the Building Regulations supports our own “Fabric First” philosophy, in

which the building envelope is the first thing to be considered in reducing emissions – and saving en-

ergy. Your SAP Assessor should work with you and/or your designer to ensure your specification

meets all aspects of Part L.

To simplify the specification process we have developed a number of packages for the superstruc-

ture walls and roof, each with indicative U-values. While these will need to be verified by your asses-

sor, the better the U-values you choose the easier it will be to meet emission requirements and sat-

isfy the Regulations. If there are difficulties in doing this, a SAP assessor should be able to suggest

suitable solutions.

An indicative price is given for your SAP assessment in your estimate.

Ground Conditions & Soil Investigations It is essential that the foundations of any building are set on firm ground. This may be limestone,

sand, gravel, clay, rock, etc. each of which will have different characteristics and ‘load bearing’ ca-

pacities. Related considerations are radiation (commonly found in granite areas), underground

streams, high water tables, and ‘heave’ – a particular characteristic of clay soils. Trees and hedge-

rows can have an important effect on these, whether or not they are still growing, or have been re-

moved in the last few years in which case their absence may cause ground water to ‘swell’ the soil

and ‘heave’ up the foundations.

Almost every development site will have different ground conditions. Some may even have different

conditions on different parts of the site.

1 Building Regulations “Part L” - http://www.planningportal.gov.uk/buildingregulations/approveddocu-ments/partl/ 2 Standard Assessment Procedures - https://www.gov.uk/guidance/standard-assessment-procedure 3 U-values - http://www.designingbuildings.co.uk/wiki/U-values

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The increasing reclamation and use of

“Brownfield” sites may require special treat-

ment of the ground, but even developing a

surplus garden area may run into former

‘tipped’, or ‘ground fill’ materials.

There is also the type of ground to consider.

Additionally considerations include the ‘slope’

of the land, any danger in taking away sup-

port for neighbouring buildings, and any po-

tential for ground source heating.

For these reasons a ground survey and report

is almost always required by whoever is going

to design the foundations and with the Build-

ing Regulation application to the LABC

Foundation Essentials Significant Savings

… can be made if the design of foundations is approached early

enough and (possibly) integrated with the structural design

and engineering of the building that they are going to support.

This is especially the case with sloping sites where, for exam-

ple, pier and beam foundations (illustrated) can be used to

‘suspend’ the ground floor.

Engineering

Different ground conditions require differently engineered

foundations and foundation design. Likewise frost and groundwater need special consideration, es-

pecially for Cellars and Basements. Avoid some early pitfalls and get your foundations right first

time. Whatever you want will need to be structurally engineered.

Don’t assume that standard, old style, trench and strip foundations will be adequate. While superfi-cially these might seem least costly, there are an increasing number of cases where poor ground conditions end up requiring very deep excavations which cost a fortune to build up with either con-crete or masonry. So make sure you obtain a suitable ground and soil survey. Basements If you like the idea of having a basement and there are no special reasons for this, like building on a very sloping site, check out the likely costs of excavating for as well as building this before commit-ting yourself to a design where the cellar or basement greatly influences the rest of your plans. Insulation This is now a critical consideration to ensure that your design can obtain Building Regulation ap-proval. Not only is the thickness of this important (200mm of rigid foam Polyisocyanurate (PIR) rigid board insulation is quite common), but the positioning of this can also be important, especially if you wish to include underfloor heating. Extensions above ground level If your extension involves the use of existing walls or foundations, you may need to have these checked by a structural engineer or surveyor to see that they can carry the load of the new structure you are putting on this. Fortunately, timber structures are light compared with masonry, so these seldom create a problem. However your LABC department are likely to want proof of this. For further information see our web pages on Foundations

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Structural Engineering & Technical Design Whatever type of structure you choose, be it Brick & Block, Timber Frame, SIP Frame, CLT Frame, etc., you will need to have this engineered and technically designed. This work is specific to each type of structure.

In the same way that the foundations support the superstructure of the building above ground floor level, the walls, floors and roof have to support and transfer the loads, or weights, that are put on them down to the foundations. These loads include things like build-up of snow and the force of prevailing winds, and the ‘dead’ loads of things put inside the building, like furniture or goods that are being stored, together with the ‘live loads’ of people and their activities in-side. Sometimes it may be necessary or desirable to add extra provisions for, say, lifting equipment or people inside and outside the building. The structural engineer calculates these loads and the route that they will take when being transferred to the foundations. Depending on the design, this may also involve the specification of special load bearing or ’stiffen-ing’ posts and beams, which may be in steel or purpose engineered timbers. These cannot be known until the engineering calculations have been carried out.

It is then the job of the Technical Designer to ensure that the superstructure of the building incorpo-rates all of these requirements, together with everything necessary for the type of structure being used to satisfy the Building Regulation requirements.

Note that these drawings are for the structure only, and not the full Building Regulation drawings, although together with the Structural Engineering calculations they do form part of a Building Reg-ulation application.

Choosing Your Structure – ‘Fabric First’ As will now be obvious, the energy requirements of any build-ing are determined by the performance of all of the elements in its encompassing ‘envelope’, i.e. the ground floor, external walls, windows, doors, and the roof including any roof lights, chimneys, or ventilators. The ‘fabric’ from which these are made and the way they are designed to connect and work to-gether affect the overall performance efficiency of the struc-ture. As noted above, the ‘Approved Documents’ in the Building Regulations set out performance requirements for these ele-ments. The way these can be achieved is left to the designer (as directed by the developer) to decide.

Subject to possible exceptions, the following table summarises our interpretation of the minimum

performance values and limiting factors for buildings required by Approved Document L – Conserva-

tion of Fuel & Power – of the Building Regulations 2013 (to be increased in 2016).

The cost of both Structural Engineering and Technical Design are included in your ‘kit’ prices.

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Conservation of Fuel and Power - Approved Docu-ment links

Ground Floor

U-value

External Wall

U-value

Party Wall

U-value

Roof U-value

Windows U-value

External Doors

U-value

Air tightness

L1A - New Homes 0.13 0.18 0.0 0.13 1.4 1.0 5.0

L1B - Home Extension 0.22 0.28 n/a 0.16 1.6 1.8 n/a

L2A - New Other buildings 0.22 0.26 n/a 0.18 1.6 1.5 (3.5) 3, 5, or 7

L2B - Other Build Extend 0.22 0.28 n/a 0.16 1.8 1.5 (3.5) n/a Notes: U-values in W/(m2K, Airtightness in m3/m’m2 @50 Pa. For existing buildings the standards used are for the new elements to be incorporated. Standards for retained elements may be different. Windows and doors not to exceed 25% of total floor area. Designers must refer to full Approved Documents and consider different values applicable in Wales & Scot-land. While these are the minimum performance standards that you must achieve, you may wish to achieve a higher levels of energy efficiency, e.g. ‘no heating’, or ‘Passivhaus’.

Rationalised Specifications & Prices To make it easier and simpler for you to decide what components and construction methods to

choose, our rationalised floor and roof ‘Fabric First’ specifications save much of the time consuming

and often confusing work involved. Simply decide which level of performance suits your needs and

budget and we can then discuss the additional elements you need and price these appropriately for

you.

The approximate U-values indicated assume masonry external skins for walls with felt, tiles and

batten for roofs.

You will also appreciate that full SAP and TER energy

calculations need to be carried out to determine the

actual insulation performance of your house, which will

be affected by the size and specification of your win-

dows and doors. Likewise the indicative airtightness

values given – which relate to the completed building -

assume that detailing, component specifications and

other works will be executed to the appropriate stand-

ards.

Depending on how you intend to build, we suggest that

you may find our “Bronze” or “Silver” specifications an economical choice. These are often appro-

priate for alterations, conversions and extensions.

If, however, yours is a completely new build or you prefer either our “Gold” or “Platinum” specifica-

tions, these will achieve even lower energy levels. However, in this case your design needs to care-

fully consider the inclusion of MVHR (Mechanical Ventilation and Heat Recovery) which will require

additional equipment and add to overall costs.

The level of airtightness will depend not only on how well the fabric of your building envelope has

been designed, but also on the way it is built on site. This is another reason why we prefer as much

of the work to be done in the factory as possible.

(see the table of Rationalised Specifications & Performance for U-values and air tightness indications)

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MVHR (Mechanical Ventilation and Heat Recovery) and Design

As your building ‘envelope’ becomes more and more efficient, it also becomes more ‘airtight’. Pre-

venting leakage of air through gaps not only saves heat and

energy losses, it also makes your home more comfortable to

live in. That is unless it becomes so airtight that it makes the

air inside ‘stuffy’ and potentially unhealthy. This starts to oc-

cur when your structure gets below around 3.0 to 2.5 air

changes per hour, so for (near) Passivhaus designs it becomes

essential.

To avoid unnecessarily opening windows and throwing away

all the gains you’ve made from having a high performance

home, an MVHR system will automatically exchange the stale

air from inside with fresh air from outside. At the same time

it will recover the heat for the outgoing air to heat up the incoming air.

An extra benefit is that the filtration system used on the MVHR removes all forms of ‘nasties’ from

the air and generally results in the quality of the air inside being better than outside.

This has been found to be really beneficial for people who tend to suffer from asthma and similar

ailments.

If you want a very airtight building with MVHR it is essential that this is decided before work on the

technical structural design and engineering is commenced. This design work must take into account

how and where the trunking, manifolds, exchange unit and other equipment are to be fitted into the

building. It will affect most key elements, like walls, joists, floors, ceilings and roof. It may also im-

pact on your interior design and lighting requirements, and so forms a crucial element for you to

consider when working up you design brief.

If your building is already designed, we can usually find ways to accommodate MVHR within the

structure by working closely with you and your design architect.

Choice Options Apart from our ‘basic shell’, all specifications include a closed ‘sarked’

roof. This not only avoids the need for underbracing of rafters inter-

fering with your roof ceiling linings, it also means that your building is

‘in the dry’ as soon as the roof structure is complete.

For Extensions our “Bronze” and “Silver” packages complement existing buildings very well, since it

may not be economical to bring the old structure up to the same levels of insulation and airtightness

as the new extension.

These packages are still appropriate for …

Completely New Buildings, but to achieve really high levels of insulation, airtightness and energy ef-

ficiency our “Gold” – possibly needing no central heating -, or “Platinum” – near Passivhaus stand-

ard - specifications should be seriously considered.

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Pick & Mix Options enable you to decide on a case by case basis what you would like to be included

in your structural ‘kit’. Your estimate sets out a set of options extracted from the package kit specifi-

cations, from which you can choose, although individually these cost a bit more than if included in a

complete pre-selected ‘package’.

Other Options - as a Chartered full design & build organisation, we can design and build using other

structural makeups if you wish. If, for example you or your architect have a preferences for alterna-

tive ‘green’ technologies, we can design, manufacture and build 250mm I-beam wall studs with

Warmcell insulation; 285mm external SIP walls and roofs, and 350mm twin wall frames with mineral

wool, sheep wool, etc. insulation. All have different U-values.

SAP’s and Finalising Your Specification As previously explained, to choose the specification for your

structural envelope you will need a SAP assessment on the

design. This will also help you decide what performance

specifications you need for your ground floor, windows,

doors, cladding, roofs, heating, ventilation, renewable en-

ergy profile (e.g. integrated MHVR, PV), etc.

If necessary we can provide SAP assessments, site & ground

survey, and related services if required.

Additional Supply & Fix Contracts The choices available for external claddings, doors, windows, roofing, stairs, PV & Solar Hot Water

and so on are vast. Most of these can only be specified

after the superstructure and the overall building perfor-

mance have been determined and affordability budgets

checked. To avoid potentially unnecessary abortive, ex-

pensive and time consuming work, these are generally

decided as the technical drawings are worked up. They

are then priced separately and ordered individually

This gives you the freedom to source and buy these separately, although as merchants to the trade

we will endeavour to provide you with the most competitive prices possible for these once they

have been finalised. These are then treated as, additional orders for supply – and fix if required.

Hybrids & Special Features As full service ISO 9001:2008 quality controlled timber

manufacturers, if you like our style, products and prices,

we will be pleased to discuss your special needs. If, for

example, you would like a mix of Timber Panel and SIP

walls and roofs, we can work with your architect to de-

sign and build this.

CAUTION: changing or adding more windows and doors will affect the energy calculations and

thus the specification for floors, walls and roof.

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Likewise, if you would like to have particular features inside your home, like vaulted beamed ceil-

ings, traditional Green Oak trusses, Post and Beam elements, full height glazed entrance frames, her-

itage style garages, car ports with rooms above, biomass Plant & Pellet stores, or free standing bal-

conies we can incorporate these in your design and manufacture the bespoke elements to your ex-

act requirements.

Indicative Full Build Costs We have also given you an indicative price range for a full ‘turnkey’ build, de-

pending on the method of construction chosen. This assumes standard devel-

oper specification

In some locations we may be able to provide some, if not all, of these services.

CDM Regulations As from April 2015 the CDM (Construction Design & Management) Regulations require anyone com-

missioning building works to appoint a ‘Principal Designer’ (who may not necessarily be your archi-

tect), and a ‘Principal Contractor’ both have specific H&S duties and both must be suitably experi-

enced as required by the regulations (see http://www.hse.gov.uk/pubns/books/l153.htm) .

If your architect is not taking on the Principal Designer’s role, please discuss this with us.

What Your Prices Include Design

- technical design

- structural engineering

- fabrication drawings

Fabrication and delivery

- selection and procurement of all materials required for your chosen kit of parts.

- manufacture of your structural kit to the level of performance you have chosen, including:-

Damp Proof Course (DPC), Sole plates & head binders

External and internal walls

First floor joists and floor deck

Roof structure

Integral garages and amenity spaces

All structural connectors and metal works (not Pro-

visional Cost [PC] sums, see below)

Delivery to you site on agreed date by articulated lorry,

or as otherwise agreed

Optional Erection of your choice of ‘kit’

including supply of nails & screws

site fixing of any extra components ordered.

Benfield ATT Group ©, 5–6 Castle Way, Caldicot, Monmouthshire, NP26 5PR, UK 01291 437 050 info@BenfieldATT.uk 14

NB: if you engage someone else to erect your ‘kit’ please arrange for them to visit or contact

our factory to check through the drawings and any special erection instructions. There is no

extra charge for one such meeting of up to 1 hour.

Your Prices pDO NOT include:- Separate Garages, Car Port, Amenities, Independent

Porches Balconies, etc. (separate prices for these)

SAP and EPC calculations

Planning and Building Regulation drawings, applications, or

fees

Project management

Material schedules or other Quantity Surveying services

Foundations or ground floor slab

Provisional Cost (PC) sums for any steel or glulam beams, etc. required by structural en-

gineering.

(We try to avoid these, but they are unknown until your design has been engineered. We

have, however, suggested PC sums for these if they are required.

Nails, screws, staples and other small fixings (unless we are erecting)

Inspections by Building Control

VAT

Note: Provisional Costs (PC) sums may be shown to avoid ‘nasty shocks’ for extra charges. These

give an indicative cost that may be incurred for items that it is not possible to determine the costs

for at the time of estimating your project, like steel work of special beams that the structural engi-

neer may decide need to be provided. Naturally we try to avoid these, but if necessary these will be

adjusted after the design has been finalised.

Rationalised Specifications & Performances Indicative U-values assume 100mm external brick cladding + clay tile roof.

SAP assessments should check these and also need ground floor, windows &

door U-values.

Each package kit includes all components for the superstructure above foun-

dation level – DPC, external; and internal walls, upper floor joists and floor

deck, and roof structure as described PLUS insulation where specified, struc-

tural engineering, technical & manufacturing design & delivery to site.

Benfield ATT Group ©, 5–6 Castle Way, Caldicot, Monmouthshire, NP26 5PR, UK 01291 437 050 info@BenfieldATT.uk 15

Timber Panel Frame Structural Insulated Panel (SIP) Frame “Standard” Basic structural kit for you to add to.

U-values: Walls 0, Roof 0, Airtight <= 7 Single sole plate to ground floor only (add more if needed). Open cell wall panels for you to insulate + solid timber joists & floor deck. Skeletal rafter roof for you to cover and insulate. “Bronze” Weather tight, 2014 Building Reg. Com-pliant

U-values: Walls 0.18, Roof 0.15, Airtight <= 6 As for Basic TF + Factory fitted 120mm PIR insula-tion Twixt studs 'Roof counter-batten + Tyvek = 9mm OSB Sarking + 165mm PIR to site fix in rafters @ 600mm crs “Silver” Enhanced Eco House

U-values: Walls 0.15, Roof 0.13, Airtight <= 5 Bronze + Polythene VCL, joint tape, 140 PIR insula-tion twixt studs inc. PIR blocks between perimeter joist ends Roof per 'Bronze' but 200mm PIR twixt rafters + Polythene VCL 12.5mm Plasterboard lining for walls (skim by others) “Gold” Possibly No Central Heating (may need MHRV)

U-values: Walls 0.12, Roof 0.11, Airtight <= 3.5 Silver + upgrade to Tyvek Reflex BM to ext. walls Adds 50mm PIR insulation outside wall wrap 59.5 PIR & Plasterboard composite lining to external walls & roof (site fix) Adds Metal web joist for MV / MVHR ducts & services Adds mineral wool insula-tion between internal walls “Platinum” Near Passivhaus Performance

U-values: Walls 0.11, Roof 0.10, Airtight <= 1 Gold + upgrade to 69.5 PIR & Plasterboard compo-site in walls Replaces polythene VCL with 'intelli-gent' Tyvek AirGuard VCL Adds air tightness kit for all external wall junctions

“Standard” SIP external walls, Open rafter roof U-values: Walls .17, Roof 0, Airtight <= 7

Single sole plate to ground floor only (add more if needed). SIP external wall panels, timber stud inter-nal walls, + solid timber joists & floor deck. Skeletal rafter roof for you to cover and insulate. “Bronze” Weather tight, 2014 Building Reg. Compli-ant

U-values: Walls 0.17, Roof 0.14, Airtight <= 5 150mm SIP walls, 175 roof, 25x38 battens inside ex-ternal walls, Tyvek BM & Counter batten to roof, 45x220 solid timber joists + 18mm/22.5mm deck, 38x89 internal wall frames “Silver” Enhanced Eco House

U-values: Walls 0.14, Roof 0.12, Airtight <= 4 175m SIP walls, 200 SIP roof, 25x38 battens to inside external walls, Polythene VCL Tyvek BM & Counter batten to roof, 45x220 solid timber joists + 18mm or 22.5mm deck to upper floors,38x89 internal walls “Gold” Possibly No Central Heating (may need MHRV)

U-values: Walls 0.12, Roof 0.11, Airtight <= 3 200mm SIP walls, 225 SIP roof, 25x38 battens to in-side external walls, Tyvek Airguard 'intelligent' VCL, Tyvek BM & Counter batten to roof, 219mm Metal web joists + 18mm or 22mm upper floor deck “Platinum” Near Passivhaus Performance

U-values: Walls 0.11, Roof 0.10, Airtight <= 1 225mm SIP walls, 250 SIP roof, 25x38 battens to in-side external walls, Tyvek Reflex to external walls, Tyvek Airguard VCL, Tyvek + counter batten to roof, 219mm M. web joists + 18 or 22mm deck

Benfield ATT Group ©, 5–6 Castle Way, Caldicot, Monmouthshire, NP26 5PR, UK 01291 437 050 info@BenfieldATT.uk 16

* U-values provided are approximate and depending on inner and outer layers. Full SAP and TER energy calculations required to determine real thermal performance. This is affected by the size and specification of windows and doors. ** Thicknesses pro-

vided are assuming 12.5 mm plasterboard and 25 mm service cavity where not noted otherwise. Excluding ventilated cavity and external cladding/brickwork. º* Full SAP and TER energy calculations required by Building Regulations to determine real

thermal performance. º** Possibly no central heating house. May need MV / MHRV. © 2010 Professor Michael Benfield. All Rights Reserved

Benfield ATT Group ©, 5–6 Castle Way, Caldicot, Monmouthshire, NP26 5PR, UK 01291 437 050 info@BenfieldATT.uk 17

How we help you create The Low Energy Buildings you’ve always dreamed of

… and add value to sustainability

Value Engineering (VE) Focusing on the various ‘functions’ of your building and its components, we identify and remove unnecessary costs while maintaining - even enhancing - its performance. Blending our extensive knowledge of all forms of timber structure, building science, regulations, and state of the art prod-ucts with your design and end user demands, we deliver highly effective, quality solutions for projects large & small, including difficult to develop sites, like soft ground, steeply sloping land and potential flood plain areas.

Design & Build (D&B) For us, Value Engineering starts with environmental plan-ning and regulatory impositions as part of our analytical and technical design processes. These feed through a drive for sustainable development into waste reduction, recycling and lean manufacture to embrace a ‘Pride in the Job’, ‘Right First Time’ mentality.

Integrated Specifications The Value Engineering of Design & Build solutions integrates se-lection of the most appropriate products, services & methods with the process. Working closely with building designers, engineers and quantity surveyors, we help select and specify those which are most functionally appropriate and cost effective. In turn this encourages the protected delivery of high

quality products, and results in time saving on-site build programmes. All of this reduces costs, enhances your project, and enables us to be the most competitive FULL SERVICE timber engineering D&B group in the UK

Key Current Considerations - Efficiency, Performance & Cost Effectiveness Our ‘Fabric First” approach to designing the most effective Building Envelopes is informed by the need to deliver highly energy efficient structures with optimum levels of insulation, minimal thermal transmission and appropriate airtightness for floors, walls, roofs, windows and doors. In the drive toward Zero Carbon and Minimal Heating requirements we offer factory Insulated Panels, SIP’s, Green Oak, Post & Beam, Glulam and Hybrid structures to achieve Code 4, 5, 6 and Passivhaus Standards.

Comprehensive Supplies Potentially, the procurement of design specific components can create un-foreseen difficulties, for example locating the source of supplies, avoiding delays in delivery lead times, quality assurance, and securing ‘best value’ products and terms. Here our long established connections, access and volume buying capabilities as manufacturers and merchants, all enable us to secure and supply such require-ments in the most timely & competitive manner as part of our Value Engineered, Design & Build methodology.

Professional Teamwork Believing that our approach to helping you create the “Buildings you’ve al-

ways dreamed of …” is distinctly different, we welcome collaboration with other construction

professionals. In doing so, our aim is to help enhance the construction team of architects,

other designers, engineers, quantity surveyors, contractors, house-builders, developers, et al,

to deliver what they and their clients both need and want. And, if end user clients like self-

builders and home provers lack any of these, to be the catalyst drawing in those that are

most appropriate for their project. To this end we offer a selective, part or full Project Management Service.

Partnering & Joint Ventures While we are happy to engage in ‘one off’

projects, the greatest benefits to industry and end user occupiers come from

the establishment of long term ‘partnering’ style arrangements with other con-

struction professionals. This can include Joint Venture arrangements for specific

developments and can be of interest to land owners and those who wish to

fund, say, housing schemes but lack the technical knowledge and industry experience necessary to make these

successful. In such cases our comprehensive team approach can be highly successful.

Benfield ATT Group ©, 5–6 Castle Way, Caldicot, Monmouthshire, NP26 5PR, UK 01291 437 050 info@BenfieldATT.uk 18

Materials Lists, Project Management, Full Turn-Key Builds If you are concerned about the quantities of materials you need, or the right price to

pay, you can now benefit from our new materials take-off, partial or full project man-

agement, or even our full turn-key building service in some areas of the UK. This is

being extended all the time.

Talk to us, or visit our factory now to discover the best way to achieve a 'Trouble

Free' project. If you do not yet have detailed drawings, planning permission, or build-

ing regulation approval, we can prepare these for you

VAT is charged on all sales, BUT is zero rated on new residential build-

ings where we are also erecting the structural frame. This means that fees for

surveys, planning & building regulation drawings, PV panels, and other items

can all be ‘zero’ rated for VAT purposes when incorporated into a contract for

us to erect a new residential building.

Please ask for indicative prices for any other components needed to complete your build.

To Discuss Your Project … just give us a call. With our housebuilding and contracting

background we are unusually well placed to help architects,

builders and self-builders talk through the implications of their

ideas and bring fresh eyes to any issues that may need ad-

dressing. We are here to help you anytime that you would like

to call us.

When you have had the opportunity of considering our prices

with your architect, please contact us to discuss how best we

can help you to realise your Low Energy Building. To make it

easy for you to do this, if possible we will have already sent

them a copy for fast and easy reference, if not we suggest you

forward this to them with attachments)

We suggest that you both arrange to visit us at our works in Caldicot (between Bristol & Newport)

a.s.a.p. to do this. Alternatively we can hold an on-line conference meeting with you, your ar-

chitect and or builder to go over your drawings in real time via computer.

If you have any queries about our ‘value for money’ approach, please call us.

WE WILL NOT BE BEATEN ON LIKE FOR LIKE PRICES

How Helpful Have We Been? It would be appreciated if, in return for our efforts in providing this information, you would be kind

enough to tell us how useful this has been for you. Any other suggestions you would like to make on

how we might improve our services would also be most welcome.

Thank you We look forward to working with you to deliver the best ‘value engineered’ Low Energy

Building for you in the near future.

Benfield ATT Group ©, 5–6 Castle Way, Caldicot, Monmouthshire, NP26 5PR, UK 01291 437 050 info@BenfieldATT.uk 19

Page for your questions & notes

Please feel free to call us or arrange for an appointment to call in and discuss your project