Proposed build-up

Existing roof build-up

Check to make sure foundations are sound before application.

Existing asphalt

Inspected for defects and made good where required.

Porosity primer

Fibrecoat porosity sealer applied using a brush or short pile roller to give an even coating across the substrate.

Fibrecoat resin system

The first layer of Fibrecoat resin is applied at 1kg per square metre depending on surface condition.

Fibremat reinforcement

150gm Fibremat reinforcement is embedded into first layer of resin with more Fibrecoat resin.

Fibrecoat resin

Final layer of Fibrcoat resin is applied at 1kg per square metre



Inspect the existing concrete deck to identify potential defects and rectify them accordingly. It's crucial to allow wet or excessively damp surfaces to completely dry before applying the Fibrecoat system.

It's also necessary to temporarily remove any lightning conductors before work begins. The lightning conductors should never be attached through the Fibrecoat membrane.


The surfaces to be coated, including any existing coatings, repairs, or test sections, must be inspected and properly repaired to ensure a solid base for the new Fibrecoat system. Any large cracks or gaps can be v-cut with a concrete crack chaser and filled with suitable material.

Ensure that all areas to be treated are thoroughly cleaned by removing dirt, debris, water, mould and moss. Use an anti-fungal wash to treat any areas ensuring all spores are destroyed and power wash to remove any left-over residue.

Any loose concrete or brickwork should be removed and repaired using a suitable mortar. Large non-structural cracks should be cleaned and filled using a structural repair mortar. For any freshly laid concrete, you must allow the roofing surface to fully cure before applying Fibrecoat. Please follow the manufacturer's guidelines for exact curing times.

Weather and temperature

The standard Fibrecoat system should only be applied if the temperature is between 3°C and 30°C. The product can be applied in temperatures as low as 1°C but special product accelerators will be required. The system must not be applied in damp, wet or conditions which could cause surface moisture.


Minimum temp


Maximum temp



Fibrecoat Porosity Sealer is a single-component, solvent-based low viscosity primer designed for use as a general-purpose primer for most well-dry porous substrates, normally concrete and porous cementitious surfaces. There is also a possibility to coat certain grades of PIR. Please contact Technical Services for more details.

Porosity Sealer is a clear liquid with excellent levels of penetration and adhesion to substrates acting as a sealer/primer before subsequent Fibrecoat installation. It should be applied using a brush or short pile roller giving an even coating across the substrate. Take care to avoid excess application or product ponding in certain areas as cure times will be extended.

Substrates must always be clean and dry before application of the Porosity Sealer. Do not apply if it is raining or rain is imminent. Porosity Sealer should not be applied to surfaces when the temperature is below 5°C and below the dew point. The temperature must be 5°C and rising. Application of the primer should not take place when wet conditions prevail, or when condensation is present or will be present on the substrate during application. Typically surfaces should be high-pressure washed with a biocide wash, free from contaminants and dry.

Porosity Sealer should be applied on smooth porous substrates such as levelled concrete and smooth cementitious materials etc at a minimum of 200 g/m². Substrates that are rough or highly porous require 300 g/m². If the coating, when dried does not have a gloss appearance, it means that the porosity of the surface is still not fully sealed and a further 2 layers at 150g/m² is required.

The Fibrecoat base layer can be applied while the primer is slightly tacky but not wet. The liquid should not lift from the substrate on touch or underfoot. Porosity Sealer cannot be used to prime non-porous substrates such as glass, metal, single ply, EDPM etc and cannot be used to prime damp or wet porous substrates such as Damp concrete & wet wooden decks etc...

Porosity sealer coverage

Typical coverage rates

Smooth concrete surface 200 g/m2


Per 20kg drum

Rough concrete surface 300 g/m2


Per 20kg drum

Application qty's will vary depending on surface condition

Porosity sealer curing

Typical curing times at 15ºc

Touch dry

Min overcoating

Full cure

Times may vary due to changing temperatures

Applying the Fibrecoat base layer

Cut the Fibremat reinforcement to the required length and width for the proposed detail to be completed. Take into account the wind when cutting the fibreglass so as not to leave unmanageable sections.

Once everything has been prepared open a can of Fibrecoat and thoroughly mix using a paddle mixer at a low rpm. Ensure the product is completely homogenous and then leave it to rest to let excess air disperse before application. This can be checked by waiting until surface bubbles disappear in the drum. This will reduce the likelihood of pinhole formation in the membrane.

Apply Fibrecoat to the detail area ensuring works are progressed to the point of egress. Immediately lay the Fibreglass Matting into the wet coating and begin to embed it with a suitable roller. Use a loaded roller to ensure full saturation of the reinforcement. Coverage rates are governed by the substrate. Refer to the specification and/or Allbase technical department for more details.

Overlaps between strips of Fibremat reinforcement must be at least 50mm with feathered edges. Ensure there is sufficient material to saturate these overlap areas.

Keeping the container warm at room temperature will assist with the application and coverage rates of the embedment coat. Cold containers will make the product thicker and more difficult to apply and therefore a reduction in coverage rate will occur.

Once the detail areas are complete, begin installation on the main roof area. Ensure overlaps onto the existing reinforced Fibrecoat sections are by at least 50mm. Apply a layer of Fibrecoat and embed it into the Fibremat Reinforcement. Apply additional material where required.

Insufficient coverage of the Fibrecoat material may make it difficult to embed the fibreglass. Flooding of the area may cause the Fibreglass to tent.

Monitor application and check for wicked fibres or pin holing and apply more product where required. Allow curing in accordance with Allbase Technical Services recommendations prior to application of the second layer. Once the membrane has cured, check for pinholes and any surface defects. Wicked fibres should be trimmed back and lightly abraded to provide an even surface prior to the application of the second layer.

Fibrecoat base layer coverage

Typical coverage rates

Smooth concrete surface 1kg/m²


Per 25kg drum

Rough concrete surface 1.2kg/m²


Per 25kg drum

Fibrecoat curing times

Typical curing times at 15ºc

Touch dry

Min overcoating

Full cure

Times may vary due to changing temperatures

Fibrecoat second layer

After application of the base coat, ensure full coverage and encapsulation of the reinforcement in accordance with Allbase Technical Services and the specification for that project. Any defective or loose areas should be cut out and replaced with new material to ensure the coating is fully bonded to a sound substrate.

Prepare the specified Fibrecoat and apply it to the detail areas first before the main area. Ensure upstands are a minimum of 150mm above the finished roof level.

Apply Fibrecoat at the coverage rate specified by Allbase; run a spike roller slowly over the freshly laid Fibrecoat to burst any bubbles and release any trapped gas before the Fibrecoat skins over. Use volume-to-area calculations to work out the coverage per drum prior to application. This will ensure the correct coverage rate is achieved. Wet thickness readings will also achieve the same result but are limited to the area chosen to test.

Check all details and main roof areas for snags and treat them accordingly. Any pinholes should be treated with extra product leaving a smooth homogenous finish. Allow curing in accordance with Allbase Technical Services recommendations.

Designated walkways should be marked out and installed only after the top coat has cured. Ensure the membrane has reached full cure before reinstating any proprietary components or plant work on the roof.

All liquid details must be suitably terminated with suitable materials such as termination bars, flashings, trims etc. Refer to the specification or Allbase Technical Services for details.

Health and safety

It is the contractor's responsibility to ensure that all relevant material safety data sheets are always on-site. Additional copies of these sheets are available on request.

In sensitive areas, it is usually possible to monitor the atmosphere for levels of VOCs and potentially hazardous fumes by using specialist testing equipment. With most products, portable site testing equipment may be used to immediately indicate the concentration of specific solvents in the atmosphere. This can show that the appropriate WEL or DNEL is not being exceeded. In rare circumstances, the services of specialist industrial hygiene companies may be required.