What a Victorian semi tells you before you open the walls

Most of my house clients live in semis built between 1885 and 1910. They are generous, well-proportioned and full of surprises. These are the ones I plan for.

Before I draw anything in an older house, I spend an hour in the basement and the attic. The basement tells you about the foundation, the water service and the wiring. The attic tells you about the roof framing and whether anyone has insulated it since 1950.

Expect these

Knob-and-tube wiring, still live in more houses than you would think, and a reason some insurers will not cover the home. Galvanized or lead water service, which should be replaced while the floors are open. Lath and plaster walls that crack when a neighbouring wall comes down. A shared party wall with your neighbour that you cannot cut into without a conversation, and sometimes an agreement.

Floors that slope 40 mm across a room are normal. I tell clients to decide early whether we level them or live with them, because leveling a main floor adds weeks and changes every threshold and cabinet height downstream.

Keep these

The things worth keeping are usually the things people want to rip out first: the original window casings, the stair balustrade, the plaster cornice in the front room. Matching that profile in new work is expensive. Restoring the original is often cheaper than replacing it, and it is what makes the house feel like itself after the renovation.

Budget a contingency of at least 15 per cent on a house this age, and hold it until the walls are open. In twelve years I have never finished a Victorian renovation without using some of it.