What is UF Foam?

Urea Formaldehyde foam is made on site to the pre-defined British Standards 'recipe'. The foam is then injected into the cavity through 19mm holes, in a wet foam state 90-95% pre expanded.

It completes its expansion by moulding itself to the unusual shapes within the cavity, and sets to form a rigid insulant by drying through the outer wall into the atmosphere.

• The raw materials for u.f. foam are manufactured under strict quality control to BS 5617 (1978) and installed in accordance with BS 5618 (1978).
• The foam is produced on site using u.f. resin and a foaming hardener.
• The foam sets immediately after injection and dries through the outer fabric of the building and into the atmosphere, as its water content evaporates.
• It has sufficient strength and stability to be self supporting in the cavity and does not collapse due to ageing or building vibrations.
• It will last for the life of the building, is chemically inert to normal building materials, and is resistant to attack by rot, fungi and vermin.
• The foam does not burn, but tends to shrivel and char when exposed to fire.
• The cured foam is resistant to water penetration and will not transmit water across the cavity by capillary action, or from below d.p.c. level.
• The foam is breathable and not a water vapour barrier, therefore it will aid the release of moisture through the wall.
• If necessary, for example to correct a building defect or when making structural changes, the insulation can be removed.

Installation Procedure

• A pre-installation survey is carried out to ascertain the suitability of the property for insulation, and to determine the position of all openings, flues and vents which need to be kept clear.
• Small holes, approximately 19 mm in diameter, are drilled both horizontally and vertically in a pre-determined pattern.
• By drilling a series of sight holes, the flow of foam may be stopped to set in a vertical line at any party wall.
• The foam is injected through the holes in a specified sequence, in order to ensure a complete fill of the cavity.
• Following the installation the injection holes are made good, and the mortar colour-matched to blend with the existing surface of the wall.

Post Installation Checks

This involves an inspection of the flues and airbricks, as well as the interior of the building to check for the presence of surplus material. If this has occurred in inhabited parts of the building, it must be removed.

Further information and useful links

• Find a Insulation Installer near you
• Find a Builder near you

• National Insulation Association
• Energy Savings Trust (est.org.uk)
• Cavity Insulation Guarantee Agency (ciga.co.uk)
• Building Regulations an explanatory booklet (odpm.gov.uk)
• Party Wall Guidance (rics.org)
• Impact of the Party Wall Act 1996 (communities.gov.uk)