Clear answers for specifying, supplying and installing P1.
Find straightforward guidance on the P1 liquid roofing system, including product use, installation, preparation, reinforcement, curing and stockist information.
Start with the most common P1 questions.
What substrates can P1 be used on?
When is primer required?
How does the reinforced system work?
Frequently asked questions.
Clear answers to common questions about specifying, preparing, applying and maintaining the P1 liquid roofing system.
P1 can be applied to a wide range of common roof surfaces including felt, asphalt, concrete and screed, liquid applied coatings, single-ply membranes, and OSB timber decks. Where the substrate is unusual or unidentified, an adhesion test should be carried out before proceeding. Some substrates — particularly single-ply membranes — require specific primers and adhesion testing; always consult the primer selector table or speak to technical support.
In normal conditions, around 15–20°C, P1 Resin becomes rain-proof in 10–20 minutes and ready for overcoating in 30–60 minutes. RapidCure chemistry is built into the system, meaning cure times as low as 30 minutes are achievable in suitable conditions. Cure times will vary with temperature, humidity, and sun exposure — always perform a test mix to confirm pot life before starting application on a new day or in changing conditions.
Yes. With the use of Low Temperature Accelerator, P1 can be applied in conditions as low as 1°C. The accelerator must be fully mixed into the resin before catalyst is added — accelerator and catalyst must never come into direct contact. At temperatures between 1°C and 4°C the accelerator is essential. Between 5°C and 9°C it is recommended. Above 10°C no accelerator is required. Always refer to the catalyst dosage table for the correct scoop rate at the prevailing temperature.
The second coat should ideally be applied as soon as the first coat has cured, and no later than 7 days after. If 7 days has passed, the surface must be abraded and wiped with acetone before overcoating. If more than 14 days has elapsed, the first coat and reinforcement mat must be reapplied. Always apply the second coat at 0.5 litres/m² to achieve the required film build.
Catalyst dosage is controlled by temperature. At 20–30°C use 2 scoops per litre. At 10–19°C use 3 scoops per litre. At 1–9°C use 4 scoops per litre. Never go below 2 scoops per litre, even in very hot conditions — high temperature inhibitor is available to extend pot life if needed. The scoop provided is approximately 25ml. Mix catalyst thoroughly for a minimum of 2 minutes until fully dissolved before application.
The 225gsm reinforcement mat must be laid with a minimum 50mm side lap and 50mm end lap. When overlapping rolls, the feathered, torn edge should always overlap the straight cut edge. Mat should be orientated to run perpendicular to the roof fall wherever possible. For trim joints and detailing, 450gsm matting cut to 75mm wide is used, applied in two layers with P1 Resin.
No. The substrate must be visibly dry with a maximum moisture content of 20% WME, measured with a Protimeter. Application onto wet substrates can cause loss of adhesion and potential failure. If rain falls during application or between coats, the affected surface must be fully dried and wiped with acetone before work continues. Gas torches and electric heat guns must not be used to dry the surface.
Standard colours are Light Grey and Dark Grey. These are the colours in which the system is manufactured and supplied. If a decorative or anti-slip finish is required for balconies, terraces or walkways, the P1 Gripcoat system is available in Anthracite Grey and other finishes.
P1 is supported by a 20-year product guarantee. When installed by a P1 Approved Installer, a workmanship guarantee is also available, backed by single-point insurance. The approved installer scheme ensures the system is installed correctly and that the full guarantee terms can be issued to the end client.
No specialist equipment is needed for standard application. P1 Resin is applied by roller, or brush where access is restricted. A straight edge and sharp knife are used to cut reinforcement mat. For catalyst mixing, the scoop provided with the product is all that is required. The system is designed to be practical and accessible for experienced roofing teams without investment in specialist machinery.
Remove any standing water using a brush, mop or wet-vacuum. Once fully dry, acetone-wipe the entire affected area — pour acetone into a bucket, soak a clean rag, and wipe the surface, changing rags frequently to avoid transferring contamination. Allow the acetone to fully evaporate, approximately 5 minutes, and apply the second coat within 15 minutes of wiping. Do not pour acetone directly onto the membrane.