HYDRONYLON HP
Base layers of the system on felt substrates, reinforced with Technical Mesh SW-1 and always finished with HYDRONYLON HN.
Prices
| Pack | Retail price |
|---|---|
| 25 kg | £224.00 (£8.96/kg) |
HYDRONYLON Approved Contractors buy at preferential trade rates.
HYDRONYLON LTD is not currently registered for VAT, so no VAT is charged - the prices shown are the final prices payable.
Where it fits in the system
HYDRONYLON HP forms the reinforced base of the system on felt roofs. It is applied in a minimum of two coats, with Technical Mesh SW-1 embedded into the second coat. It is never used on its own: the build-up is always completed with the HYDRONYLON HN top coat.
How the system worksTechnical parameters
| Role in the system | Base layers on felt substrates |
|---|---|
| Colour | Grey |
| Pack size | 25 kg |
| Consumption, first coat | Approx. 0.8 kg/m² (1.0 kg/m² on new coarse-grained felt) |
| Consumption, second coat | Approx. 1.2 kg/m², applied through Technical Mesh SW-1 |
| Total consumption | Min. 2.0 kg/m² (min. 2.2 kg/m² on new coarse-grained felt) |
| Number of coats | Min. 2 |
| Interval between coats | Min. 24 h |
| Application conditions | +10°C to +35°C around the clock, relative humidity up to 85% |
| Storage | +5°C to +30°C; use within 30 days of opening |
System performance (ETA-23/0735)
| External fire performance | B(roof)(t1) |
|---|---|
| Reaction to fire | Class E |
| Watertightness | Watertight |
| Wind load resistance | Pass (> 50 kPa) |
| Working life category | W2 (10 years) |
| User load category | P3 (Normal) |
| Roof slopes | S1 to S4 |
| Surface temperature range | -20°C (TL3) to +80°C (TH3) |
| Minimum dry film thickness | Felt 1.8 mm, metal 0.7 mm, mineral 0.75 mm, PVC 1.2 mm |
| Notified Body | No. 1454 (Łukasiewicz - Warsaw Institute of Technology) |
Coverage
- Total consumption on felt is a minimum of 2.0 kg/m² across two coats, rising to a minimum of 2.2 kg/m² on new coarse-grained felt.
- Example: a 50 m² felt roof needs at least 100 kg of HYDRONYLON HP, which is four 25 kg buckets. On new coarse-grained felt allow at least 110 kg, which is five buckets.
- Complete felt build-up materials cost: £34.89/m² (materials only; HYDRONYLON HP 2 kg, HYDRONYLON HN 1 kg and Technical Mesh SW-1 1.05 m² per m²).
Application notes
- Apply at +10°C to +35°C around the clock, at relative humidity up to 85%; never on wet or frozen substrates or during rainfall.
- Apply a minimum of two coats: the first at approx. 0.8 kg/m² (1.0 kg/m² on new coarse-grained felt), the second at approx. 1.2 kg/m² through Technical Mesh SW-1 with overlaps of at least 10 cm.
- Allow a minimum of 24 h between coats.
- HYDRONYLON HP is never used as a standalone finish: always complete the build-up with the HYDRONYLON HN top coat.
- Mix before use and do not dilute. Clean tools with warm water and detergent.
Downloads
- Retail price list 2026 (PDF)
- European Technical Assessment ETA-23/0735 (PDF)
- UK Declaration of Performance 2026 (PDF)
- HYDRONYLON HP technical data sheet (PDF): available soon.
Frequently asked questions
Can HYDRONYLON HP be used on its own?
No. HYDRONYLON HP forms the reinforced base of the build-up on felt and is always finished with the HYDRONYLON HN top coat, which provides the final weathering surface of the system.
How much HYDRONYLON HP do I need?
Plan for a minimum of 2.0 kg/m² across two coats, or a minimum of 2.2 kg/m² on new coarse-grained felt. For a 50 m² felt roof that means at least 100 kg, which is four 25 kg buckets.
How long should I wait between coats?
Allow a minimum of 24 hours between coats. Apply only at temperatures between +10°C and +35°C around the clock, at relative humidity up to 85%, and never on wet or frozen substrates or during rainfall.