An extension that matches the existing house, not a bolt-on beside it
The tell on a bad extension is never the plan. It is a mortar joint three millimetres too pale and a course line that does not run through.
Why an extension is not a small new build
The commonest failure in London extension work is treating the new structure as a separate building that happens to touch an old one. Detailed that way it will always read as an addition, however good the internal finish is, because the eye reads junctions before it reads rooms.
We survey the existing fabric before the extension is detailed: the brick, the bond, the mortar colour and joint profile, the course heights, the reveal depths, the way the existing rainwater goods land. Those measurements drive the detail drawings rather than being reconciled to them afterwards.
Matching brick, in practice
London stock varies street to street and often within one elevation, and a brick that matches under a showroom light frequently does not match in April daylight. So the match is made on site, against the actual wall, in daylight, with samples laid up wet.
Mortar does at least as much work as the brick and gets a fraction of the attention. Colour, sand source and joint profile are specified and sampled the same way. Where a genuine match is not obtainable — and on some Victorian stocks it is not — we say so before the contract, and we detail the junction deliberately instead of pretending.
- Existing bond, course heights and reveals measured before detailing
- Brick matched on site in daylight against the actual elevation
- Mortar colour, sand and joint profile sampled, not assumed
- An honest junction where a true match does not exist
The junctions that give it away
Where the new roof meets the old, where the new floor level meets the existing, where a new opening interrupts a run of original skirting: these are the places a good extension is decided.
They are also the places that cost time rather than money, which is why they are the first thing squeezed on a job that is running late. A programme with the junctions costed into it from the start is how they survive.
Where each of these is evidenced
- Extensions we have delivered, photographedProjects →
- The extension service in fullExtensions →
- Period detail and original featuresHow we build →
Can you match a Victorian London stock brick exactly?
Often, but not always — and where a true match is not obtainable we tell you before the contract rather than after the scaffold comes down. In that case the junction is detailed deliberately, which reads far better than a near-miss.
Does matching the existing cost more?
The brick itself sometimes does. The larger cost is time in the detailing and on site, which is why it has to be in the programme from the start rather than found later.
What if the existing brickwork is in poor condition?
Repointing and repair of the adjoining elevation is priced as its own line in the bill of quantities, so you can see it and decide on it separately.
See the range before you speak to anyone.
The estimator gives you a band in a couple of minutes, and tells you how wide it is and why. If you would rather talk it through, that works too.