What usually goes wrong with cross-wall houses?

Most problems are in the front and rear infill panels: timber decay, water getting in where panels meet the cross walls, poor insulation and worn cladding. Fire separation between neighbouring homes also needs checking.

Can the front and rear panels be replaced?

Yes, but replacement is building work that is likely to need Building Regulations approval, and it must maintain fire separation between homes and the stability of the building. Ask the seller for approvals for any past replacement.

Why do cross-wall houses often feel cold?

The lightweight panels and large windows of the period often have little insulation, and air can leak at the junctions with the masonry walls. Upgrades are possible but need careful detailing.

Cross-Wall Construction Houses: A Guide

Q: Is cross-wall construction non-standard?

It depends on the lender. The main structure is usually masonry, so some lenders treat it as standard. Others treat it as non-standard because the front and rear walls are lightweight panels. Check with your lender or broker before you pay for a survey.

What it is

In cross-wall construction, the floors and roof are carried by load-bearing walls that run from front to back, usually the walls between neighbouring homes. Historic England describes it as a terrace or block of flats supported on walls set at right angles to the main front and back walls.

Because the front and rear walls carry little or no load from the floors and roof, they could be built as lightweight infill panels: timber frames finished with tile-hanging, timber boarding or sheet cladding, often with large areas of glazing. The cross walls are usually brick or block. Cross-wall construction was used for many terraces and town houses in the 1960s and 1970s.

How to recognise it

Brick or block walls between houses that show at the front and back of a terrace, with panels between them.
Front and rear walls that are tile-hung, boarded, clad or largely glazed, often spanning the full width between the cross walls.
Front and rear walls that sound hollow when tapped inside.
A terrace or group of town houses of the same design, often from the 1960s or 1970s.

The EPC wall description depends on how the assessor recorded the walls, so treat it as a clue only.

Common problems

Infill panel decay. Timber sole plates, sills and the lower parts of panels can rot where water gets in or cannot drain away.
Water getting in at junctions. Where panels meet the cross walls, and around windows, sealants and flashings age and fail.
Cladding. Tile-hanging, boarding and sheet cladding need maintenance. Slipped tiles, split boards and corroded fixings let water in.
Thermal performance. Thin panels, large windows and draughty junctions make these houses harder to heat, and can lead to condensation.
Fire separation between homes. The wall between two homes should form a fire-resisting barrier all the way up to the roof. Gaps where panels, cladding, fascias or the roof space pass across the line of that wall can let fire spread from one home to the next, and the fire stopping is usually hidden.
Stability. Removing internal walls or making large new openings can affect how the building resists sideways movement, so changes should be designed by a structural engineer.
Materials of the period. Asbestos can be found in any building built before 2000, and some panels and claddings of this era may contain it. Get an asbestos survey before any work that disturbs them.
Replacement panels. Panels and windows may have been replaced over the years, to varying standards. Ask for approvals and guarantees.

Mortgages and insurance

Lenders do not all treat cross-wall construction the same way. Some regard it as standard because the structure is masonry. Others treat it as non-standard because the front and rear walls are lightweight panels, particularly if they are timber-framed and clad. Some may ask for more information about the panels or any replacement work. Check with your lender or broker before you pay for a survey, and describe the construction accurately to your insurer.

What we check

In a Level 3 Building Survey of a cross-wall house we:

confirm the construction and the type of infill panel
inspect panels, sills and junctions closely, using a moisture meter where suitable
check cladding, windows, flashings and sealants
look in the roof space at the walls between homes for gaps in fire separation, where they can be seen
use a drone to look at the roof, including any flat roofs, where flight is permitted
note alterations and replacement panels, and ask for approvals

We cannot see inside the panels. Where there are signs of decay or water getting in, we may recommend opening up or a specialist inspection. Where alterations raise questions about stability, we recommend a structural engineer.

What we have found locally

Reports that recorded cross-wall construction:

8 DBISS survey reports since 2022

Our cross-wall records include homes in St Albans, Hemel Hempstead, Slough and Oxford, in villages around High Wycombe and in north Oxfordshire, and in Walton-on-Thames. In any cross-wall house, the infill panels and their junctions with the cross walls deserve the closest look.

Sources

Historic England: Listing Selection Guide, Domestic 4: The Modern House and Housing
GOV.UK: Fire safety: Approved Document B
Health and Safety Executive: Asbestos
RICS: House surveys (UK): the costs, types and benefits of an RICS Home Survey