Defect diagnosis and remedial design

Common causes fall into a few families and each is investigated on its terms. Foundation movement, from clay shrinkage under nearby trees, subsidence, heave, made ground or leaking drains, shows in a characteristic pattern that we relate to the ground and the seasons. Overloading and past alterations, where a wall was removed or a load added without proper support, show as deflection and cracking along the new load path. Material decay, such as rusting reinforcement, corroded steel, rot in timber and expanding wall ties, works from the inside and needs opening-up to confirm. Lateral instability, bulging walls and spreading roofs, shows as bowing and separation.

We match the investigation to the suspected cause: trial pits and soil information where foundations are in question, opening-up where decay is suspected, drain surveys where washout is possible, and monitoring where we need to know if it is still moving. We assess the ground-related cases in line with Eurocode 7 and set the findings against the loads the structure actually carries. The point of this stage is a firm diagnosis, because a repair designed against the wrong cause is money spent that does not fix the building.

Once the cause is clear the repair follows from it. Foundation problems may call for underpinning, root barriers, drain repairs or, where movement has stabilised, simply careful crack repair and monitoring. Overloaded or altered structures need the missing load path reinstated with new beams, columns or restraint. Decayed elements are strengthened or replaced with attention to why they decayed, so the repair lasts. Bulging and spreading are pulled back into line with restraint straps, ties or new lateral support. We design the specific scheme, not a generic one, so the builder has something buildable and Building Control has something to accept.

We also design the sequence, because a structure with a defect is already carrying its loads and the repair must not make things worse before it makes them better. That means temporary support and a safe order of work built into the design, especially where underpinning, beam replacement or removing decayed elements is involved. Where the defect affects a shared wall or a neighbour, we coordinate with the party wall process. We agree a single fixed fee agreed before we begin, and we serve clients across the UK.