Timber Frame vs Brick Extension: Which Is Right for Your Home?
Updated: 5 days ago
You want more space, and before you get anywhere near a design, you need to decide how the extension gets built: timber frame or traditional brick and block. Both give you a solid, permanent room. Where they differ is speed, insulation, usable space, how they look and what they mean for planning. Here is how the two compare, based on the extensions we build around Reading and Berkshire.
Timber frame vs brick extension: what is the difference?
A timber frame extension is built around a structural frame of engineered timber panels, usually made off site, with the insulation built into the walls. A brick and block extension is built on site course by course, with an outer leaf of brick, a cavity and an inner leaf of blockwork. Both can look identical once finished.
We build timber frame extensions in Reading using a pre-engineered insulated panel system. The panels arrive ready to assemble, so the structure goes up in days. A brick shell rises a few courses at a time and relies on dry, frost-free weather to keep moving.
What does not change is the groundwork. A timber frame is lighter, but a timber frame extension still needs proper foundations, just like brick.
Build time: where timber frame pulls ahead
On the projects we run, a 30 square metre timber frame extension typically takes 9 to 12 weeks on site, against roughly 14 to 18 weeks for brick and block. Factory-cut panels mean the structure can be standing within a few days of the foundations being ready.
Brick is slower for a simple reason. Mortar does not cure properly in freezing conditions, so a winter brick build can stall for days at a time. Timber frame is far less weather-dependent, which keeps the programme on track through the colder months.
For most homeowners, finishing several weeks sooner makes a real difference. That is less time with builders in the garden and less time living around the work.
How timber frame and brick and block compare
These are the points we talk through with every homeowner before they choose:
Insulation and running costs. Timber frame walls reach lower U-values at the same thickness, so the room stays warmer in winter and costs less to heat.
Internal space. Because the walls are thinner for the same insulation, timber frame gives you around 20 per cent more internal floor space than brick and block on a narrow plot.
Weather and programme. Timber frame goes up and becomes watertight quickly, so rain and frost cause far fewer delays.
Appearance. Brick blends in with most UK homes straight away. Timber frame can match it using brick slips or render on the outside.
Sound. Brick and block is heavier, so it blocks more noise as standard. A timber frame needs acoustic insulation in the walls to match it.
Maintenance. Brick is close to maintenance-free once built. A timber frame needs to be detailed properly against moisture at the build stage, then needs very little attention afterwards.
Disruption. A shorter build means fewer deliveries, less mess and a garden you get back sooner.
Neither method is the right answer for every home. The best choice depends on your timescale, your plot and the finish you want.
Are timber frame extensions cheaper than brick?
Usually, yes. On a like-for-like single-storey build, timber frame typically comes in around 8 to 15 per cent cheaper than brick and block. Most of that saving comes from the shorter build: fewer weeks of labour and site costs.
The gap narrows on very small jobs, where the speed advantage is smaller, and when you finish the outside in brick slips to match the house. Foundations, glazing and the internal fit-out cost much the same either way. We go through the numbers in our guide to how much a timber frame extension costs.
Can you build a wooden extension on a brick house?
Yes. A timber frame extension can be built onto a brick house, and it is one of the most common jobs we do. The new frame is fixed back to the existing brickwork and the joint between old and new is sealed against water, so the two structures work together as one.
A wooden extension does not have to look wooden from the outside. The frame sits behind the outer finish, so you can choose:
Brick slips to match your existing brickwork
Render for a clean, modern look
Timber or composite cladding if you want a contrast with the house
What the planning rules say about materials
The finish you pick can affect whether you need planning permission. Under permitted development rules, the materials used on the outside of an extension must be of a similar appearance to the existing house. A timber frame finished in matching brick slips can sit within those rules. Timber cladding on a brick house usually means applying for planning permission.
In conservation areas, National Parks and other designated land, permitted development does not allow exterior cladding at all. If your home is in one of these areas, plan for a planning application whichever finish you choose.
Separately, most extensions need Building Regulations approval, whatever they are built from. We cover the size, height and boundary limits in our guide to building a timber frame extension without planning permission.
Timber frame or brick and block extension: which should you choose?
If you want a faster, less disruptive build and a warmer room, timber frame is usually the better choice. You also get a little more usable space inside the same footprint, and it tends to cost a bit less.
Brick and block still has its place. If you are matching a period property in a conservation area, or you want the most soundproof walls possible and do not mind a longer build, brick is a sensible option.
For most extensions on most homes around Reading and Berkshire, timber frame gives you the same finished room, built sooner and cheaper to run once you are living in it.
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