What it is
No-fines concrete is made with cement and coarse aggregate, such as gravel, but without sand, the "fine" aggregate. Leaving out the sand leaves small gaps between the stones, which gives the concrete an open, honeycomb-like texture. It is lighter than ordinary dense concrete.
The building firm George Wimpey used no-fines concrete for large numbers of houses from the 1940s to the 1970s, many of them for local councils. The walls were cast on site by pouring the concrete into reusable shuttering (formwork). Upper floors and roofs were often built in the usual way, in timber. The outside of the walls was usually rendered to keep out the weather.
No-Fines is not a precast reinforced concrete (PRC) system, and it was not among the house types designated defective in the 1980s. Our PRC houses guide explains what designation means.
How to recognise it
- Rendered walls with no brick courses, often on an estate of houses of the same design built at the same time.
- Neighbouring houses of the same design, some of which may have had insulation added to the outside.
- In the roof space, gable or party walls with the rough, open texture of no-fines concrete: small stones with gaps between them and no sand.
- An EPC that describes the walls as "system built".
Many No-Fines houses have been clad with external wall insulation, which hides the concrete and changes their appearance. The roof space and the paperwork then become more important.
Common problems
- Cracking. Cracks often start at the corners of windows and doors, where stresses concentrate as the concrete shrinks and moves with changes in temperature. They need to be assessed for width, pattern and whether they are still moving.
- Corroding steel. Where steel was cast into the walls, for example over openings, it can rust and expand, causing cracking and rust staining.
- Render. The render keeps rain out of the concrete. Cracked, hollow or bulging render lets water in, and patch repairs in an unsuitable material can make matters worse.
- Cold walls and condensation. Uninsulated concrete walls lose heat readily. Cold spots at window heads, floor edges and corners can lead to condensation and mould, especially in kitchens and bathrooms.
- Wall insulation. External insulation can make a No-Fines house warmer. Badly detailed insulation can let water in at the base, around windows or at the eaves, and it hides the wall behind. Ask for details of the system, the installer, any guarantee and any building control records.
- No cavity. In its usual form there is no cavity, so there are no cavity wall ties to corrode. Cavity wall insulation is not suitable, so insulation has to go on the outside or the inside.
- Alterations. New or enlarged openings, and extensions tied into No-Fines walls, need a properly designed beam or lintel and support.
Mortgages and insurance
No-Fines houses were not designated defective, and many lenders will consider them. Some ask for a satisfactory report from a structural engineer first, and some will not lend on them at all. Policies vary between lenders and change over time, so ask your lender or broker before you pay for a survey.
Tell your insurer the construction type when you ask for a quote, and check that the policy covers it. Your conveyancer should check the paperwork for any insulation, alterations or repairs.
What we check
In a Level 3 Building Survey of a No-Fines house we:
- confirm the construction as far as a visual inspection allows, including from the roof space
- record cracks, especially around openings, and look for signs of corroding steel
- check the render, or any external insulation, for cracks, bulges, damaged edges and water getting in at the base and around windows
- look for condensation, mould and cold spots
- note alterations such as new openings and extensions, and ask for approvals
- use a drone to look at the roof, chimneys and gutters, where flight is permitted
Where cracking, corrosion or an alteration raises questions that a visual inspection cannot answer, we recommend a structural engineer. An engineer's report is also what some lenders ask for.
What we have found locally
Reports that recorded Wimpey No-Fines construction:
10 DBISS survey reports since 2022
Our No-Fines records include homes in Hemel Hempstead, High Wycombe, Slough, Borehamwood and Baldock, and in the HA3 postcode district of Harrow. If you are buying an ex-council house in these areas, it is worth asking about the construction early.
Sources
- Hansard: Housing Defects Bill, second reading, House of Commons, 26 April 1984, which lists the PRC types to be designated
- legislation.gov.uk: Housing Act 1985, Part XVI
- BRE: SAP 10 and RdSAP 10 specifications, which define the wall types used on EPCs
- RICS: House surveys (UK): the costs, types and benefits of an RICS Home Survey