Timber Frame vs Brick Extensions: An Honest Comparison

Timber frame or brick is one of the first questions clients ask about an extension, and most of the answers online come from someone with a product to sell. We build both, so we have no side to take. The honest answer is that for most London extensions the finished result can be excellent either way, and the right choice comes from your site, your programme and your priorities, not from the material itself.

A masonry extension is built the traditional way: blockwork and brick, wet trades, the structure rising course by course. A timber frame extension is engineered as panels, often manufactured off site, then erected quickly and clad in whatever finish you choose, which can still be brick. That last point surprises people: a timber frame extension can look identical to a masonry one from the street. The structural choice and the appearance are separate decisions.

Timber frame's headline advantage is programme. Panels arrive engineered and go up in days, the structure is weathertight sooner, and follow-on trades start earlier, which matters when every week on site is a week of disruption to your household. Masonry is slower to rise but forgiving on site: dimensions can flex, changes are absorbed more easily, and there is no lead time on a factory slot. If your design is settled and speed matters, timber frame earns its keep. If the design may evolve during the build, masonry tolerates change better.

On a typical single storey London extension the two routes usually land closer together than the marketing suggests: what you save in programme and labour with a frame, you spend on engineering and manufacture. Where the ground is poor, timber's lighter structure can genuinely save foundation cost; where access is tight, panel delivery needs thinking through. As a realistic anchor from our own priced projects, new high-standard extension space in London generally runs 2,400 to 2,800 pounds per square metre before VAT and professional fees, whichever way the structure is built. The structural route moves the number less than people expect; specification and glazing move it far more.

A well-detailed timber frame is warm: insulation sits within the frame depth, so good thermal performance comes easily. Masonry brings mass, which many people read as solidity and quiet, and which helps rooms stay cool in summer. Both routes meet building regulations comfortably when detailed properly; the failures we see are workmanship failures, not material ones. If a particular feel matters to you, the heavy hush of masonry or the crisp warmth of a framed structure, say so early, because that preference is a legitimate design driver.

In practice the decision usually falls out of three questions. How settled is the design? How much does programme matter to your household? And what is the ground like? We price both routes from real projects, put the numbers side by side, and let the difference argue for itself. If you are weighing an extension, The Estimator on this site will give you a realistic range for your postcode in minutes, and when you are ready to compare routes properly, talk to us.