Spray Foam Insulation

Room in a roof insulation

The versatility of in-situ applied WALLTITE® insulation foam makes it an ideal material for use in loft conversions.

It can be applied to external solid or cavity walls, separating or party walls, knee or side walls, flat and pitched roofs.

WALLTITE® automatically provides designers with a more airtight roof. It prevents the ingress of wind blown rain, snow and dust and other forms of airborne pollution.


WALLTITE® has undergone various performance tests. Certificates are available on request.

LABC RegisteredNBS Plus

Technical specifications

Existing pitched roof, ceiling at rafter line

Target U-value: 0.18W/m²k 150mm of WALLTITE

WALLTITE is applied between the rafters in sloping ceiling areas, either directly onto the underside of slates or tiles, or onto a membrane of low vapour resistivity.

Plasterboard is then fixed to the face of the rafters.

New flat roof

Target U-value: 0.18W/m²k 140mm of WALLTITE

WALLTITE is applied directly to the underside of the plywood decking, between the roof joists. When used in conjunction with spray applied foam, any external weatherproofing must be of low vapour resistivity, e.g. single ply membranes.

External Cavity Wall

Target U-value: 0.30W/m²k 50mm + 35mm of WALLTITE

Injection grade foam can be injected through a series of evenly spaced holes, normally drilled in the outer leaf. This closed cell foam is totally resistant to driving rain. In a residential property, the cavity is usually continuous from the ground floor to the apex of the roof. In this case the whole elevation must be filled. For a nominal 50mm cavity you would need to top this up with 35mm sprayed to the inner leaf.

Party Wall

Target U-value: 0.30W/m²k 95mm of WALLTITE

For solid wall insulation, WALLTITE is sprayed between metal or timber studs.

Plasterboard is then fixed to the face of the studwork.

Knee or side wall

Target U-value 0.30W/m²k 95mm of WALLTITE

WALLTITE is sprayed between the timber studs of the wall. Plasterboard or ply is used as a backing board. Plasterboard is fixed to the face of the studwork, on the warm side of the wall.

Typical detail

Room in a roof insulation

Room in a roof insulation

  1. 100mm x 50mm rafter
  2. Unventilated air space
  3. Plasterboard and skim
  4. Flooring
  5. WALLTITE® CL 100 insulation to achieve target U-value

Habitable space: plasterboard and skim/VCL with taped joints VCL to be carefully cut and sealed around struts, ceiling joists and penetrations); batten/counter batten rafters as necessary to achieve insulation depth, confirm rafter strength sufficient to receive counter battening and boarding if required.

Loft space only, non habitable: insulated between and over rafters to achieve target U-value. WALLTITE® may remain exposed.

Additional resources

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