Home / Knowledge / Encapsulation Rayston Spray Foam HFO 40
Encapsulation Rayston Spray Foam HFO 40
Engineer notes. Not a blog. Encapsulation build. Rayston Spray Foam HFO 40 (rigid two-component polyurethane foam) is the recorded insulation.
Rayston Flex 3040 (medium-modulus polyurethane sealant) is named with that foam. Impermax Polyurea H Flex Alum (hybrid polyurea with aluminium pigments) is the waterproofing. Therefore the specifier writes the commercial name and the chemical type in the same sentence. Foam is not the membrane.
The recorded build
First, name the insulation: Rayston Spray Foam HFO 40 (rigid two-component polyurethane foam, HFO blowing agent) with Rayston Flex 3040 (polyurethane sealant) for movement. Then name Impermax Polyurea H Flex Alum (hot-spray hybrid polyurea with aluminium pigments). Catalogue 2026 lists that finish as UV-stable without a separate aliphatic topcoat. The job record applies it as a fast-curing two-component membrane whose pigments are written to hold colour in solar exposure.
Do not specify a separate Colodur sealer on this Alum clause unless the current TDS says so. Also, do not invent a kilogram rate. Read consumption from the current sheet, then the calculator.
How to specify the encapsulation build
Name foam, joint sealant and Alum polyurea as three products. Keep HFO foam distinct from a hybrid polyurea. An aluminium appearance is a pigmented membrane, not a paint.
See asbestos encapsulation, thermal and acoustic insulation of roofs and products. Documents stay on /documents/.
Official project: kryptonchemical.com — new encapsulation work.
Outbound reference: EOTA.
Depth pins in the foam are a site control. They are not a thickness claimed in these notes.
These notes do not replace the current TDS, SDS or a written specification. For pack sizes, mix ratio and kg/m², read the current sheet, then the calculator.
