1.2 Stone-faced scattered felt roof repair proposal

Coating of a stone-faced scattered felt roof

General

This repair method proposal is indicative and deals with the coating of stone-surfaced roof felt with ElaProof H, S and ElaProof Cool Roof coatings. There must be no previous coatings on top of the stone-surfaced roofing felt. If previous coatings are found, it is necessary to make sure of the adhesion of the ElaProof coating to the previous coating by performing a separate adhesion test.

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

Platform inspection

Before coating with ElaProof products, it is necessary to check the condition of the original felt roof with a stone surface. Especially on roofs with several felt layers on top of each other, the roof felt bulges. Usually, this is due to the intense heat stress that occurs during the summer, when the different felt layers may separate from each other. If these bumps occur, it is appropriate to repair them before coating. The repair is done by cutting off the detached area from the roofing felt and patching it with a corresponding type of roofing felt, following the roofing felt manufacturer’s instructions for attaching the roofing felt.

Also check the seams of the roofing felt to make sure they are not coming apart. If there is separation in the seams, fix the detached seams with bituminous glue intended for gluing roof felt.

It is typical for some aggregate-surfaced roof blankets that the aggregate is weakly attached to the surface of the blanket. Since ElaProof coatings form their adhesion primarily to this aggregate, it is possible that when the aggregate loses its adhesion to the felt, the coating also remains a floating film in this respect. For this reason, it is recommended to carry out a trial coating of approximately 1 m² on the roof in a place that is exposed to the heat of the sun before coating the entire roof. Let the test area dry for at least 7 days and try to remove the coating film from its edge. If the aggregate comes off easily with the coating from the surface of the felt, it is possible that bubbles will appear in the coating later on. In this case, contact Build Care Oy’s technical service to resolve the matter.

Note! It is possible to influence this matter mentioned above by choosing the lightest possible e.g. white ElaProof coating for use, in which case the color of the coating lowers the surface temperature of the roof.

Platform preparations

All branches, leaves and other loose debris and impurities accumulated on the roof are removed.

The roof to be coated is washed with a suitable high-pressure washer and detergent, e.g. Biocomb Puhdas Katto Extra Strong or SikaGard-715W.

After a longer dry period, larger roof surfaces can also be cleaned with so-called as dry brushing using a combustion engine powered brushing machine. Even after this cleaning method, the roof must be treated with a detergent and water that destroys moss and algae growth.

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 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 sprayed roof before spraying to avoid splashes (reduces the need for protection). If necessary, ElaProof H coating can be thinned 1-2% with water to make working easier.

ElaProof H coating is applied with a spatula, brush or short-pile roller. ElaProof H coating is recommended to be applied to the area to be coated in 2 separate application times. The total material consumption for loose felt roofs is 1.6-1.8 l/m², in which case the dry film thickness is min. 1.0 mm.

ElaProof S and ElaProof Cool Roof spray coating is 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 the ElaProof S and ElaProof Cool Roof spray coatings to the area to be coated in 2 separate application times.

The total material consumption for loose felt roofs is 1.6-1.8 l/m², depending on the coarseness of the felt aggregate, in which case the dry film thickness is min. 1.0 mm.

ElaProof H, S and 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