Simply put, your roof protects your home
from the harsh elements of Caribbean weather.
Getting the best performance from that protection,
begins with your treatment of roof sheets
prior to, during and after construction.
Our overall advice for roof construction is to keep all design and assembly as clean and simple as possible. This creates ease of building, post construction maintenance and replacement.
The less that a roof sheet is moved, machined or handled to its final site, the less its surface is liable to installation compromise.
Given the recent change in weather patterns and
the voracity of storms, we recommend that you review your roof and guttering security on a regular basis,
to maintain your first line of protection.
COLORBOND® and ZINCALUME® are tried and tested worldwide. In order to maximise that high quality performance
we present a list of best practices.
The following apply to our complete range of :
13 COLORBOND® colours in 24 and 25 gauge
and Zincalume® in 24, 25 and 26 gauge steel,
in three profiles.
All matching RidgeCaps and Flashing.
NB. Overall sheet width is 32” [81.28cm], sheet overlap is
2” [5.08cm]. Please calculate sheet width as 30” [76.2cm]
Care and Storage
Do not store sheet packs out in open weather.
Material should be stored dry at all times, therefore cover stack with a tarp and stack sheets, or bundles clear of the ground to avoid material getting wet.
Should material get wet, unpack wet sheets to allow drying.
Use a clean cloth to remove surface moisture, and stack in
such a way that air circulation completes the drying process.
Cutting Sheets on Site
Cutting should not be carried out on top of other roof sheets.
Use metal blades rather than carborundum discs or angle grinders, as they produce fewer damaging hot metal particles, leaving fewer burs on the cut sheet.
BHP recommends the use of cold cutting saws such as the Makita® 4130 unit with the appropriate blade.
You may also use a sheet metal nibbler or an electric drill nibbler fitting to achieve required cutting results.
Bending and Roll Forming
Roll-forming and bending of COLORBOND® steel should preferably be done without the use of a lubricant.
Do not use kerosene or distillate on COLORBOND® steel, as they soften the paint film.
Don't exceed the minimum bend radii, as this could crack the protective film.
Touch up paint is not recommended to repair surface scratches on COLORBOND® steel. The different weathering pattern of touch up paint will lead to an inconsistent colour across the sheets’ surface. It is recommended that damaged sheets be replaced.
If the COLORBOND® steel sheet is only scratched back
to the ZINCALUME® steel coating, leave the scratch bare,
as the sacrificial properties of Zinc will produce an oxide to protect the surface from corrosion.
If the sheet is scratched back to the cold rolled metal base and the scratch is greater than 2mm wide, sacrificial protection will be reduced and those sheets should be replaced.
Do not leave metal articles on the roof.
Remove all metal scraps, pop rivet mandrels and excess fasteners from the roof at least daily to avoid rust stains.
When cleaning up after having installed roof sheets clean out
the gutters, ensuring not to leave metal tailings.
Walking on Roof Sheeting
Clean soft-soled shoes should be worn.
Dunlop® Volley shoes are recommended for use when installing and inspecting roof sheets.
Keep weight evenly distributed over the soles of the feet as new sheets may be slippery.
Walk on purlin lines wherever possible.
Detergents and Cleaners
Never use abrasive or solvent type cleaners (turpentine, petrol, kerosene, paint thinners) on COLORBOND® steel surfaces.
Never use wire brushes, steel wool or sponge scourers to clean the roof sheet.
Only non-ionic detergents or “kitchen” detergents are recommended for cleaning roof sheets. (A soft cloth, mop or soft nylon bristle brush may be used).
Lead and copper are not compatible with COLORBOND® steel
or ZINCALUME® steel products.
Always use coated steel purlins and girts to avoid any ZINCALUME® or COLORBOND® steel contact with bare steel
or treated timber.
Ply-Foil®, a multilayer, reflective roofing insulation, can act as an effective long term barrier, while reducing 96% of the radiant roof heat.
Use of Sealants
Do not use acetic acid based sealants.
While being ideal for use with other materials, they liberate aggressive by-products during curing which is detrimental to sheet steel.
These often have a vinegar or ammonia smell.
Use neutral cure silicone rubber sealants which offer the following:
- Good adhesion to the clean surface of roof sheeting.
- Water resistance and are non-corrosive to the sheeting.
- Resistance to extremes of heat and cold while retaining good flexibility.
- Provide high resistance to ultra-violet rays (sunlight) and have a long service life.
Mineral turpentine is suitable for cleaning only the surfaces to be adhered and remove all residual solvent with a dry cloth. While spirits such as Shell X-55 can also be used to clean the surfaces to be sealed.
Fasteners and Accessories
Do not use galvanised steel ridge cap flashings or gutters with a ZINCALUME® steel or COLORBOND® steel roof.
The galvanised steel will need to be replaced at an earlier interval.
Use ZINCALUME® or COLORBOND® steel instead.
Do not use stainless steel screws, galvanised washers, cadmium plated screws or other type of screw that doesn’t comply with AS 3356 Class three, with ZINCALUME® steel or COLORBOND® steel, as this will lead to premature failure of the roof sheet.
All screws should have rubber sealing washers.
Rubber washers should be EPDM quality or the equivalent and be free of carbon fillers.
Buy fasteners that are as durable as the roof sheeting you have purchased and that comply with class AS 3566 Class 3. AS3566 is a performance based standard that specifies a minimum coating thickness for fasteners to be used in benign (Class 1) to severe marine (Class 4) environments.
Do not allow brick cleaning fluids to spray onto or flow across sheeting and into gutters.
This can lead to early failure of the paint and corrosion of the metal. Instead, ensure that brick work that sits above or adjacent to a section of roof, is cleaned before roof and gutter installation.
Do not mount roof air conditioning units on CCA treated timber.
Also do not place CCA treated timber or green hardwood dunnage on roof sheets.
Pipes and other penetrations made from copper or lead must be post painted to prevent the deposition of metallic copper or lead ions upon the roof surface. Failure to comply with this requirement will result in the accelerated corrosion of the roof sheet. Any mortar or concrete should be removed immediately from roof sheets.
These are technical guidelines.
Every roof and every job has its own eccentricities
and to meet those challenges, our experienced sales staff are available to answer specific questions which will arise in the construction process.
You can download this document
for your future reference here:
Be ready for the next hurricane season.
- Check your roof for weaknesses and update if necessary.
- Check your gutters and downpipes for obstructions.
- Clean your drains on and off your property.
- Heed all official warnings and don’t take unnecessary risks.
- Store plenty of drinking water.
- Keep important documents and items together in a waterproof container
along with dry clothes, medicines, battery powered devices and essential items.
NB. This article is for general information purposes only and is meant as an incentive to the reader, who should then research and seek advice from their architectural and construction professionals to confirm that the ideas expressed are possible within the building codes of their territory or within the limitations of their home's architecture. ECMIL only recommends their own products and third party products which they supply, as part of their company's roofing solutions to customers.