How undersetting works
Undersetting replaces the bottom of the wall. We remove a short section of the salt-damaged brick or stone at the base, down to the footing, while the sections either side are left in place as pillars holding the wall up. We lay a new plastic damp-proof membrane, rebuild the section with sound materials and fresh mortar, and let it set hard before the next section comes out.
Working in alternate sections like this means the wall is supported the whole way along, and it is never left in a dangerous state. When every section is done, we trim the excess membrane, acid wash the wall and clean up the path.
When a wall needs undersetting
Undersetting is the fix when the base of the wall is too far gone to save: bricks or stone that have crumbled, mortar that has turned to sand, or an old damp course that has failed completely. Its big advantage over injection is that the worst of the damaged, salt-saturated material comes out and is replaced, instead of staying in the wall.
If the masonry is still sound, injection is quicker and cheaper. We do both, so we’ll tell you honestly which one your wall needs.
Our own tradesmen
Undersetting is structural work on the wall that holds your house up. We never subcontract it: our own tradesmen do every section, and the people who quote the job are the people who do it.
Questions about undersetting
Can rising damp be fixed for good?
Yes. A new damp course stops the ground moisture and salt climbing the wall. The important part is fixing anything that bridges it, like garden beds, paving or render built up over the damp course, or it will come back. We back our work with a 30-year guarantee.
How long does a damp wall take to dry out?
It depends on how wet the wall was, how thick it is and the weather. A solid masonry wall dries slowly, so we’ll tell you when it is ready to plaster and paint rather than guess.
How much does undersetting cost?
It depends on the length and thickness of the wall, what it is built from and how much has to be replaced. We come out, look and give you a free written quote, and we will beat any written quote.