Renovations in Carshalton

Water is the thing that makes Carshalton different. The ponds, the Wandle rising nearby and the ground conditions that come with them all matter to anyone renovating an older house in SM5. The stock around the ponds and the park includes properties considerably older than the standard London terrace, built in lime mortar with solid walls, shallow foundations and floors sitting close to outside ground level. Those houses reward sympathetic work and punish the wrong materials fairly quickly. Understanding how a building was meant to handle moisture is worth more here than any product promising to stop it.

Older Buildings and the Right Materials

Solid walls built in lime were designed to absorb moisture and release it again. Sealing them changes that balance, which is why hard cement render, dense modern plaster and impermeable paint so often produce damp where none was reported before, usually at skirting level or in the corner of a north facing room. Repointing in an appropriate lime mortar, using a breathable plaster system internally and improving ventilation is slower and less dramatic than an injected treatment, and it addresses the cause. We survey what a wall is actually made of before specifying anything to put on it.

Floors and joinery follow the same logic. Suspended timber floors need their underfloor void ventilated, and airbricks lost beneath later paths, patios or render are one of the most common causes of decayed joist ends in these houses. Original sash windows are usually worth repairing rather than replacing, since the timber in them is better than anything sold today. Where a house has been altered over centuries rather than decades, opening up carefully and finding out what is there before committing to a layout saves a great deal of rework.

Ground, Water and What the Engineer Decides

Low lying ground near a watercourse means the water table deserves attention before any design is fixed. Checking the flood map for the property is a straightforward thing to do early, and it changes what is sensible below ground level. Lowering a floor or forming a basement in a house near the ponds calls for a full understanding of ground water, underpinning and waterproofing, and it is not something to approach by digging first and thinking afterwards. Where it is viable, it is designed by the structural engineer and built strictly to that design.

Ordinary extension work is simpler but still led by the ground. Trial holes reveal what the existing foundation actually is, which on older buildings is often very shallow, and the new foundation depth is set by the engineer from what is found rather than from a standard figure. Building control inspects the open excavation before any concrete is poured. Access, at least, is easier here than in inner London, since most properties have a driveway or frontage where a skip and materials sit off the road, which keeps the street clear and the job tidy.

Where most Carshalton projects start: whole-house refurbishment in Carshalton, everything we cover across Sutton, renovations in Wallington and full house renovation cost.