Main OfficeUmicore Building Products USA Inc.Magnolia Building, suite 1043120 Highwoods BoulevardRaleigh, NC 27604 Tel.: + 1 919 874 7173Fax: + 1 919 874 7140

www.vmzinc-us.cominfo@vmzinc-us.com

West Coast OfficeUmicore Building Products USA Inc.208 Southwest 1st AvenueSuite 304Portland, OR 97204 Tel.: + 1 503 827 0600Fax: + 1 503 827 0770

This manual is intended as a supplement to PRO-ZINC®

training.

Contents include highlighted points on VM ZINC® to give thecontractor a general overview of this durable and versatilematerial.

The field installer is encouraged to refer directly to the areasof the manual which relate to his concern. Terms used inroofing vary regionally.

A Umicore brand

Architect: Stanley Saitowitz

Double Lock Seam ManualVM ZINC®

1

VM ZINC®

General information

The origin of zinc as a roofing material

dates back to the early-nineteenth

century Europe. Its use has grown to the

extent that today zinc is Europe’s number

one choice for metal roofing.

History

Between 1450 and 1500 the first

drawings were shown with single and

double seam techniques.

UMICORE

For over 160 years, UMICORE BUILDING

PRODUCTS has been providing innovative

building solutions for architects and

contractors around the world. Today

UMICORE BP is the world’s leading supplier

of zinc-based architectural products for

roofing, facades and rainwater systems.

Clearly, VM ZINC® is the superior choice for

metal roofing.

Qualities

Composition

The 99.995% pure zinc is alloyed with

small amounts of titanium, copper and

slight traces of aluminum for increased

strength, creep resistance, and less

thermal expansion.

Patina

VM ZINC® forms a natural protective layer

or patina. This process takes two to three

years and depends on the availability of

water and air.

Pre-weathered

Because the patination process occurs over

a period of time, and the material may

appear uneven in coloration during this

process, UMICORE BP offers two pre-

weathered surfaces:

- QUARTZ-ZINC®: a phosphatation is used to

create the aspect of naturally weathered

zinc - a dark grey.

- ANTHRA-ZINC: a phosphatation process is

used to create an almost black/slate-

effect zinc.

- NATURAL ZINC: Shiny as it comes out of

the mill, is also available.

>

QUARTZ-ZINC®

>NATURAL ZINC

>

ANTHRA-ZINC

direct exposure to ultra-violet rays and/or

apply an approved protective coating to

the VM ZINC®.

• Concrete, cement mortar

Wet concrete or mortar accidentally spilled

on VM ZINC® will stain the surface of the

material if not washed off immediately.

The staining is an aesthetic defect and

will not the affect the mechanics

performance of the zinc components.

• Sealants

Most sealants used in the roofing industry

are silicone-based. Some of the sealants

contain acids that will cause corrosion.

Use only VM ZINC® approved caulk and

sealant. Call our office for a list of

approved sealants.

2

VM ZINC PLUS®

A 60 micron thick liquid polymer heat-

adhered to the backside of the VM ZINC®

seals the metal to eliminate backside

corrosion and allow the material be

installed over incompatible substrate and

in warmroof applications without the use

of a”ventilation membrane”. VM ZINC

PLUS® can formed and shaped under

normal conditions as the coating will not

crack or split. When soldering, the coating

must be cleaned from the surface.

Lifespan

The longevity of zinc as a building

material is influenced mainly by the

thickness of the material and the

environment in which it is installed. In

conservative terms you can count on 90 to

100 years in rural areas, 40 to 70 years

near the sea, and 30 to 40 years in heavy

industrialized environments. Many

buildings in Europe still have their original

nineteenth-century roofs.

Zinc in relation to other metals

In the presence of moisture, the metal

with the highest potential in the electro-

chemical scale decomposes the metal

with a lower potential and causes its

destruction, over time, by accelerating

corrosion.

Because of this, it is necessary to be

careful when mixing metals to avoid

potentially harmful interaction. Combining

zinc and copper in the presence of water

creates an electric charge. As water runs

downhill, it transfers with it particles of

the material it crosses. For this reason, it is

important to avoid having a copper roof

above a zinc roof.

VM ZINC®

General information

Zinc in relation to various woods

When laying VM ZINC® on wooden

substrate, or installing wooden siding

above VM ZINC® components, care must be

exercised in the type of wood used. Wood

with a pH of less than 5 must be avoided

since it can have a corrosive effect on VM

ZINC® in the presence of humidity.

Plywood may also cause a problem in

terms of acidity and the presence of

tannins or phenolic glues.

Zinc in relation to other materials

• Bituminous felt

Bituminous felt must not be installed in

direct contact with or above zinc

components. With exposure to moisture

and sunlight, bituminous felt creates an

aggressive acid, which can stain or corrode

the zinc.

Bituminous corrosion is a common hazard,

and can be prevented with a protective

coating applied on regular basis.

Protect the bituminous membrane from

Al Pb Cu SST StAluminium Lead Copper Stainless steel Galvanised steel

ZINC + + - + +

+ permissible

- not permissible

Compatible Incompatible

Pine LarchSpruce Oak

Scots Pine ChestnutPoplar Red Cedar

Douglas FirWhite Cedar

3

PRO-ZINCBefore you start

Special consideration must be given for lead-time in material orderingand duration of installation. Remember, you are installing a roof systemthat is intended to last for multiple generations. Utmost care must be given to details, and procedures must be followedstrictly. The general contractor, the project manager, and the architectshould be made aware of these considerations and plan accordingly.“Failure to plan is a plan to fail.”

Sheetmetal contractors’ experience

Installer Qualification

Engage an experienced field installer who

has experience in sheet metal roofing

similar in material, design, forming

method, and to the extent indicated for

this project. Provide evidence of installer

participation in Umicore Building Products

USA Inc.® PRO-ZINC Training Course.

PRO-ZINC Training

Manual is not a substitute for

PRO-ZINC Training

You can’t learn to ride a bike by reading a

book and you won’t learn the craft of

installing VM ZINC® by reading a manual.

Umicore Building Products is proud to

employ master craftsmen specially trained

in VM ZINC® installation technique. It is

their job to provide training and technical

support to the field installer. This training

is mandatory for all installers of VM ZINC®.

Lead time for material orders

The majority of VM ZINC® roofing and wall

panels are stored in the continental USA.

However, each project is distinct in

character, and lead times vary. It is

important to maintain contact with your

responsible Technical Marketing Manager.

Handling recommendations

Avoid dropping zinc sheets, coils or

formed pieces: blows or punches in the

material can cause folds or bumps in

one or several parts of the sheets or

coils, which in turn can damage the

appearance of the product. Furthermore,

cracks may occur in these places over

time.

Avoid dragging or sliding of all products

over rough surfaces: deep scratches in

the material can also cause cracks

either during forming or after

installation, due to the effects of

expansion and contraction of the metal.

Avoid large temperature variations

during transportation: temperature

variations can cause condensation build-

up, which in turn will cause zinc

hydroxide (“white rust”) on the metal.

When shipped by containers, it is

essential to ventilate the containers

immediately upon receipt and store the

products as soon as possible in the

correct conditions outlined below.

Storage recommendations

Sheets and coils of zinc must be stored

in a well-ventilated, sheltered and dry

warehouse, with a constant

temperature to avoid condensation

build-up.

The humid conditions of the

southeastern United States may warrant

the use of de-humidifiers in the storage

facility.

4

PRO-ZINC

Sheets and coils of zinc must be

separated from the ground by a pallet,

to allow sufficient air space for the

proper ventilation of the products.

In order to avoid deformation of the

metal, sheets must be stored flat on the

pallet.

When coils are shipped, they may be

placed either eye-to-the sky or eye-to-

to the side, depending on the client’s

request. It is recommended that the

coils be stored in their original

packaging. If coils are to be stacked due

to lack of storage space, the following

recommendations must be respected:

- if coils are delivered on their horizontal

axis, the pallets must be stored in their

original packaging, and preferably

individually on separating racks;

- if coils are delivered on their vertical

axis, the pallets may be stored on top of

one another, up to a maximum of 4 pallets

for reasons of stability.

The time of storage of sheets and coils

must be as short as possible, especially on

site.

Protective film

Protective film comes standard on most

VM ZINC® products. The product should be

installed with the protective film in place

to help prevent scratches. The film should

be removed promptly after installation,

since the film is not UV resistant and

residues of the adhesives may remain on

the metal.

UMICORE BP recommends that the

protective film be removed no later than

six weeks after the date of installation.

Tools and machines

Hand tools

The double lock standing seam roofing

system is hundreds of years old. Naturally,

there have been many developments in

the area of tools. Zinc metalcraft has some

unique and very important considerations.

For example: cuts must be perfectly

smooth; never use shears with a serrated

edge. The turning radius on bends should

be rounded at the brake point to avoid

potential cracking. Seldom should a metal

hammer be used to strike the zinc. Always

use an approved plastic mallet for shaping

and seaming. See our website:

www.vmzinc-us.com, to purchase

recommended sets of tools.

Brakes

If your shop is equipped with a press-style

metal brake, use your most round radius

die. This applies to bench brakes as well.

Use the manufacturer’s most rounded

press bar and adjust the brake bar to

material thickness. When using a typical

bench brake or portable, and a round

radius pressbar is not available, try the

following procedure:

Loosen the tension on the brakebar. Start

your bend approximately 1/8” before the

desired brake point and bend only to

about 1/3 the desired bend degree. Move

the metal to the desired brake point and

complete the bend.

Note: Always consider material thickness

and turning radius in measuring.

Rollformer

Few rollformers are appropriate for

forming VM ZINC® panels. As with the

metal brake, the panels require subtle

radius bends as well as lateral allowances

for expansion and contraction. For these

reasons, Umicore BP strongly recommends

the use of our preformed panels.

5

Installation

Seamers

Seaming, or welting, is the most

important element of the double lock

standing seam system. There are three

main ways to seam VM ZINC®:

- with plastic mallet and anvil,

- with a variety of hand seaming tools,

- with an electric mechanical seamer.

Panel lengthStandard lengths are 33’ (≈ 10 m). Lengths

greater than 40‘(≈ 12 m) have been

successfully installed with specific Umicore

Building Products recommendations, and

function without any problem.

The standing seam method ensures maximum waterproofing in snowyregions or in areas of heavy rainfall. In addition, it offers very goodwind resistance in extremely windy areas. Regarding aesthetics, thelow height of the seams contributes to the modernity, lightness andregularity of the roofing in its architectural function. Installing a doublelock standing seam roof system gives the metalcrafter the opportunityto demonstrate his talent.

Seam Height Panel width 19 11/16” (500 mm)

1” (25 mm) 16 15/16” (430 mm)

1 1/2” (38 mm) 15 11/16” (405 mm)

Minimum slope1:12 (≈ 5º) is the minimum required slope

for VM ZINC® Double Lock Standing Seam

roof systems.

Panel widthUmicore Building Products provides sheets

and coils in 19 11/16” (500 mm) as

standard. The center-to-center distances

between seams will depend on the height

of the seam being created. Refer to the

table for approximate distances between

each lateral seam.

Note: Clips between panels will add to the

overall lateral spacing.

6

Sub-construction

Pine wood3/4” close-jointed pine is probably the best

wooden substrate for VM ZINC®. Joints

should be no more than 1/2”(12 mm)

apart. Minimum width of board is 3 1/2“(90

mm). 3/4” (19 mm) tongue and groove

boarding is also permitted.

Plywood

Exterior grade 3/4” plywood is an approved

roof deck for VM ZINC®. It is advisable to

use plywood with the highest number of

laminations available.

Particle board or OSB

Is not permitted.

Mineral wool

Is permitted. The minimum allowable

density is 11lbs/ft3. See VM ZINC®

structural roof.

Foam glass

Is permitted according to the VM ZINC®

specifications.

See the manufacturer’s recommendations

or VM ZINC® COMPACT ROOF.

Underlayment

Tarpaper, organic felt, and bituminous

membrane typically used to dry in the

building are not compatible with VM ZINC®

and must be avoided. The acidity and

water-holding tendencies of these

products will severely damage VM ZINC®.

Natural metal installations in the past have

required a slip-sheet such as rosin paper

between the metal and the substrate.

Installation

UMICORE BP has developed ROOFSHIELD®

to accomplish dry-in and slip-sheet in one

step. Roofshield must be used with ZINC

PLUS.

ROOFSHIELD® by proctor

ROOFSHIELD® is adapted to temporary

protection of the roof work. It is UV

resistant and can stay uncovered for 2

months.

Because of its water vapor permeability,

water trapped under the membrane

before the installation of the zinc panels

can be eliminated by vapor diffusion.

ROOFSHIELD® also acts as a slip-sheet

allowing the free expansion/contraction of

VM ZINC®. It also separates VM ZINC® from

incompatible substrate.

Clips

UMICORE BP has done extensive

research and development in the area of

fixing and sliding clips. VM ZINC® clips

shall be the only clips ever used. They

have been specifically engineered for the

VM ZINC® Roof System and must be

spaced and screwed as specified. The clips

are designed to withstand negative load

requirements, control creep while allowing

expansion, are non-corrosive, and have

minimal impact on the outward

appearance.

Fixing clips

VM ZINC® Fixed Clips: 300 Series Stainless

Steel Clips. Thickness: 0.024” (0.6 mm).

UMICORE BP manufactures a roof system with exact specifications forunderlayment, clips, fasteners, panels, detail solutions and installationpractices. Deviation from specifications will jeopardize the life span ofthe roof and therefore voidany warranties.

Sheet clips

Flashing and joints at lateral seams shall

be fixed with the use of sheet clips to

avoid water infiltration and possible

tearing during thermal movement.

>

>>

The clip is pre-punched with counter-sunk

holes for attachment.

Sliding clips

VM Zinc® Expansion Clips: 300 Series

Stainless Steel Clips. Thickness: 0.024” (0.6

mm) fixed base with 0.020” (0.5 mm)

thick sliding part. The sliding clip base

incorporates 2 3/4” (70 mm) slot to permit

movement. The clip is pre-punched with

counter-sunk holes for attachment.

7

Installation

Position of fixing and sliding clips

VM ZINC‚ sliding clips and fixed clips shall be placed every 18”. For a distance of 1/8 of

the length of the roof on all eaves, ridges, and rakes, clips shall be placed 12” on

center with a minimum of 3 clips.

Location of fixing clips depends on roof slope. Use the chart above to determine the

location of the fixing clips on your roof.

Note: Use five fixing clips unless otherwise specified.

Screws

All fasteners must be seated in pre-punched, countersunk holes of VM ZINC®. Clips to

eliminate the potential for contact and abrasion between fastener head and panel.

Fastener head profile shall eliminate telegraphing through metal panel. Fasteners shall

be selected to resist all negative design load requirements. Minimum pullout strength:

112 lbf (50 daN)

Note: Do not use screws other than those specified without consulting our Technical

Engineering Department.

Recommendations

- VM ZINC® Oval Head Self Drilling 316 Stainless Steel Fastener by SFS Stadler

80, 120 & 160 mm with 4,8 mm thread diameter

- #10 deck screws, 8 mm bugle head, #2 square drive, 316 stainless steel

8

InstallationPanel layout

Hints for layout

Use chalk lines to establish your layout and help maintain

alignment. Opinions vary on seam direction in relation to the

main wind direction. The prevailing school of thought among

UMICORE Building Products trainers is that is it best to start in the

middle of the roof with a double male leg starter panel and work

in two directions.

End panel

If the end panel’s width falls on the layout so that it is 8”

(20.5 cm) or less, take the last two panels and divide them into

two equal panels larger than 8” (20.5 cm).

The width of the end panel shall not exceed the regular panel

width. This is very important, because along with the ridge and

eave, the rake receives heavy wind uplift. Narrow end panels

will put more clips where they are needed most.

Panel length

The common panel length for the double lock standing seam and

angle seam is 33’ (≈ 10 m).

Larger strips have to be divided in two or more pieces.

Special VM ZINC® sliding clips allow strips larger than 33’ (≈ 10 m),

but extra attention has to be paid on every detail to compensate

for the increased thermal movement.

Transverse seams

When the length of the roof exceeds the maximum allowable

length, it is necessary to join the panels using transverse

junctions.

Seaming

Seaming, or crimping, is where the two panels are connected

and joined to the clips. This is a critical phase of the double lock

standing seam system. It is important to remember that the

Double Lock Standing Seam roof is rain-safe, but not watertight

unless extra measures are taken to make it so. (e.g., use of

UMICORE Building Products seaming oil).

Hand seaming

The softness and malleability of zinc make its shaping, forming,

and seaming attractive to the metalcrafter. Care must be taken

when hand seaming to avoid punctures and scratches. If

hammering, only close seams with a plastic mallet using an

anvil as backside support. Do not close seams too tightly.

Machine seaming

Before the mechanical crimping of the up-stands, the first fold of

the up-stand is formed manually using first seam closing tools

every 3 feet (≈ 1 m). Consult the owner’s manual for your

machine for it’s particular operating instructions. Then be sure to

monitor the operation closely.

Cold weather installation

All metals become more brittle when they are cold. If the

temperature of the zinc is not at least 45ºF (7ºC) when it is

installed, it may be subject to brittle fracturing.

When working in cold environments, particularly over several

days, the zinc should be stored in a dry, warm place. Many

electrical seaming machines have heating units available. Please

check with the manufacturer of your specific seaming machine.Single transverse seam >= 5 : 12 (25°)

Double weld transverse seam >= 2.12:12 (10°)

Roofstep >= 1 :12 (3°)

Don’t be deceived by the appearance of straight vertical lines and conclude that panel layout is simple or

could be taken lightly. A well-planned layout strategy will save time and enhance appearance. It is advisable

to take diagonal measurements to assess how square the sub-construction is.

9

Double lock standing seamdetails

Details

Two distinct characteristics of VM ZINC®

are:

- It will outlast any available sealant

- Changes in temperature have a

dramatic effect on the material.

The details used for Double Lock Standing

Seam roofs have been developed in

Europe, over the last several hundred

years, with these characteristics in mind.

Note: The following are three-dimensional

illustrations of the described details. Use

the Web-link to access more thorough

schematics.

Eave detail

How hot is it today?

Is your metal at is full rate of expansion?

If you are installing in very hot weather, you have to leave more

space between the eave flashing and the bend in the panel than

if you are installing in cooler weather. Never crimp eave

terminations tightly, to avoid capillary action.

Ridge detail

The commonly used Z-Bar will not be practical for VM ZINC®

because the panel shall never be through-fastened. The PRO-ZINC-

style ridge detail allows lateral movement while eliminating any

possibility of water infiltration. Perforated zinc is used for

ventilation at the ridge.

Perforated zinc greatly diminishes vermin or insect infestation,

but also reduces airflow by ≈ 50%. What this means is that if your

roof requires a one-inch ventilation slot, you should have two

inches of perforated zinc area.

High snow areas require the use labyrinth-style ridge-caps.

10

Double lock standing seamdetails

Hip detail

Opposing roofs, when using VM ZINC®, must be separated. Hip

details generally look best if terminated in a manner similar to

the ridge. This, unlike seaming, separates the roof areas and

allows independent movement.

Rake detail

There are a variety of approved rake terminations. A handsomely

executed edge lends distinction to your project. Use an approved

edge and never use screws, rivets or nails through its surface.

Remember to leave 1” (25 mm) space between the rake fascia

and the edge metal.

Inside corner

The inside corner shall be folded in a manner as to negate the

use of cuts, caulk, rivets, etc. Most installers are pleased to find

that this long-lasting solution is also the quickest.

Penetrations

Roof penetrations pose a major challenge in VM ZINC® roofing. A

chimney or pipe may create a fixed point in the roof, and

possibly a maintenance requirement. Proper executions of

flashing details will lessen the impact of penetrations on thermal

movement.

Chimney

Chimney cladding is a focal point of PRO-ZINC and can only be

completely explained with proper training. Basic points to

remember are:

• Leave space for expansion (approx. a finger width).

• Flashing shall turn a minimum of 6” (≈ 15 cm) up all sides.

• Never fix flashing directly to the chimney

• A chimney that exceeds 36” (91.44 cm) requires a water-

diverting cricket.

• Recommended counter flashing is a continuous termination bar

style.

• Reglets let into the masonry are not recommended.

Plumbing

Pipe penetrations must be centered in the panel. A penetration

in the seam will leak and lead to failure.

Carefully locate pipes on the layout by coordinating with the

plumber. Pipe boots must be cone-shaped to allow movement.

≈6”

11

Maintenance

Special considerations

It is inevitable that someone is going to have something they

need to put on the roof which requires special consideration.

Some examples might be:

• Satellite dish,

• Lightening rod,

• Antennas, etc...

Finding a solution involves your sense of how a VM ZINC® system

roof functions. Do not create a fixed point or through-fastening.

Often a conical flashing similar to a pipe boot is the best

solution. When in doubt always consult with your VM ZINC®

team.

Maintenance

Cleaning

The natural cleaning process of wind and rain is the preferred

means of cleaning VM ZINC®. More aggressive cleaning measures

should be used only in areas of necessity. Heavy dirt and

decaying leaves may be swept or blown off and the metal may

be rinsed with a standard pressure hose. High-pressure cleaning

may damage the patina pre-weathered surface.

14

Factory formed double lockstanding seam panels

Not all Roll formers are set up to form zinc panels, in fact

most of them are not. The radii in the bends for zinc are

different to the ones typically used for other metals. Zinc

being a more brittle material than others might crack when

being bent in the wrong (too sharp) angle.

The details that the architect has used to detail the job are

details that are based on the roll forming capabilities of

Umicore Building Product equipment.

Some roll formers when not being set up to form zinc might

enhance the waviness in zinc and lead to unwelcome oil

canning. Unusable panels that you produce are at your costs

because you would have to buy new zinc to replace them.

Our panels and the related fasteners are a system and

guaranteed to fit and work together. If you break up this

system you are responsible for its performance, of what is

now your system.

Umicore Building Product panels are UL-rated. If you make

your own panels that would not be the case unless you go

through the necessary motions and costs to have them rated.

Many of you might have roll forming equipment at your disposal andmight be tempted to form your own panel. Umicore advises that youpurchase panel formed zinc panel in lieu of sheets & coils.

Roll forming on site or in your warehouse takes precious time

away from your staff. Typically the hourly rates of a

roofer/sheet metal worker are higher than those of shop

workers. Your installed costs would typically be lower if you

purchase preformed panels

If you let Umicore Building Product form the VM ZINC® panels

- the quality insurance and management of the panels is "on

us". Hence you would have the advantage of having the

refining of the metal, it's rolling and the manufacturing of

panels in one hand. This leaves only one party to talk to for

all your technical questions and concerns.

Most Architects and Owners like our standard eave detail as

shown on page.9 and consequently specify it. As described on

page 4 of this manual there are hand tools available for

purchase to do this detail. Still hand-notching on side requires

skill, patience and time and might cause delays in the laying

process. If you purchase panels from Umicore Building Product

you can order the eaves on the concerned panels pre-notched

that brings your installation labor costs significantly down.