1.1 Factory-coated tin roof repair proposal

Coating of a factory-coated tin roof

General

This repair method proposal is indicative and deals with the coating/sealing of a PVC, Plastisol (PVC), Pural, Acrylic (AK) and Polyester (PE) paint-coated tin roof with ElaProof H, S and ElaProof Cool Roof coatings.

The repair proposal is not a repair plan. The overall design of coating/sealing is always the responsibility of the site-specific designer.

Inspection of the platform

Before coating with ElaProof products, it is necessary to check the type, condition, surface cracking and especially adhesion to the substrate of the original tin roof coating. The type of coating can usually be found out most easily on the back of the plate. Adhesion of the original coating can be evaluated with a cut test (so-called X-cut test) or a grid test according to the EN ISO 2409 standard, if the thickness of the paint film is less than 250 µm. In the X-cut test, cross cuts are made on the surface with a sharp knife through the coating. If the original coating comes off with a knife blade at the intersection of the cuts, the adhesion to the substrate is weak and may cause the original coating to come off again after recoating. If the adhesion is weak and/or the original coating is detached from its substrate in large areas, it is recommended to remove all the original coating. The surface cracking of the original coating should also be checked, e.g. with a 50 x magnifying optical device. Abundant surface cracking also causes the need to completely remove the original coating.

Platform preparations

All branches, leaves and other loose debris and impurities accumulated on the roof are removed. Smaller areas with peeling or flaking of the original coating are delineated by removing the loose areas down to a solid coating.

Any rust is removed with a wire brush or sanding in such a way that all loose rust material can be removed.

The roof to be coated is washed with a suitable high-pressure washer and detergent, e.g. Tikkurila Panssaripesu, Teknos Rensa Steel Peltipesu, Biocomb Pure Roof Extra Strong or SikaGard-715W.

Anti-rust

Rusty areas and metal-clean surfaces can be primed with water-based paint suitable for rust prevention, e.g. Tikkurila Rostex Super Akva or Teknos Ferrex Aqua. In rusty areas, it is also possible to use rust converters, e.g. Tikkurila Rust Converter. Always follow the instructions of the manufacturer of the product intended for rust treatment regarding the time window for further treatment.

Patching of holes, cracks and seams

Small holes and seams do not require special measures but can be bridged with ElaProof H coating. Larger holes and seams (width over 2 mm and depth over 5 mm) are recommended to be patched reinforced with ElaProof Roof reinforcement fabric.

When patching larger holes, you should also check the underside of the sheet metal cover. If there is a significant amount of rust, the underside of the cover should also be treated with ElaProof H coating when patching, in order to make the rusted area oxygen- free.

Possible overlapped joints of sheets in the sheet metal roof, where there is no separate sealing, should be treated with a combination of ElaProof H coating and ElaProof Roof reinforcement fabric before the actual coating.

Sealing of penetrations

ElaProof H coating and Elaproof Roof reinforcement fabric can be used to seal the penetrations in the roof when their adhesion surfaces are metal or PVC plastic.

If necessary, ElaProof H coating can be thinned by 1-2 % with water to make working easier. The ElaProof Roof reinforcement fabric is raised as a collar against the penetration to a height of at least 20 mm. If the grommets to be sealed allow a preformed grommet to be threaded over the grommet as a collar, the grommets can be shaped from ElaProof Roof reinforcement fabric if necessary.

If the grip surfaces of the grommets are EPDM rubber, PP plastic or PE plastic, it is recommended to use cloth-coated Butyl tape or a cloth-coated Butyl rubber grommet on which the ElaProof coating is applied as a grip bridge in the area to be raised as a collar.

Coating with ElaProof coating

ElaProof H coating is used, if necessary, for coating the entire roof, but most commonly for patching, sealing penetrations and treating the edge areas of the roof to be sprayed before spraying to avoid splashes (reduces the need for protection).

If necessary, ElaProof H coating can be thinned by 1-2 % with water to make working easier.

The ElaProof H coating is applied with a spatula, brush or short-pile roller. It is recommended to apply the ElaProof H coating to the area to be coated in 2 separate application times.

The total material consumption for tin roofs is min. 1.0 l/m², in which case the dry film thickness is min. 0.6 mm.

ElaProof S and ElaProof Cool Roof coatings are applied with an airless high-pressure sprayer suitable for the purpose. The injection pressure must be 170-300 bar and the yield min. 6 l/min, The recommended nozzle sizes are 527-529 and 627-629. It is recommended to apply ElaProof S and ElaProof Cool Roof coatings to the area to be coated in 2 separate application times. The total material consumption for tin roofs is min. 1.0 l/m², in which case the dry film thickness is min. 0.6 mm.

ElaProof H, S and ElaProof Cool Roof are rainproof for 3-7 hours after coating, depending on the prevailing temperature and relative air humidity during the work. Build Care Oy recommends that the average daily temperature during ElaProof coating is at least 10 °C.

The coating reaches its full mechanical properties after approx. 3 weeks. After that, the surface can be painted over if necessary, for example.

Overpainting

If, for example, the desired color shade cannot be found in the ElaProof coating, it is possible to paint the ElaProof coating. The painting should be done with the tested water-thinned tin roof paints recommended by Build Care Oy, which are e.g.

Note! Repainting is not a necessary measure but is only carried out if necessary.

Build Care Oy owns all rights to this repair proposal. Designers can freely use this repair method suggestion when preparing repair plans!

ALWAYS READ THE PRODUCT DATA SHEETS FOR THE PRODUCTS PRESENTED IN THE REPAIR PROPOSAL BEFORE STARTING THE INSTALLATION!

Structural drawings

All structural drawings related to ElaProof products in DWG and PDF format from the ProdLib-Service.

Updated: 08/2023 | JKo