Are Timber Frame Extensions Cheaper Than Brick? What the Numbers Show

You are weighing up an extension and the budget hinges on one choice: timber frame or brick. Most people assume timber is the cheaper option, and a lot of the time it is, but the full picture is more interesting than a simple yes. Here is how the two compare on cost, build time and the things that quietly add up, so you can plan with realistic numbers rather than guesswork.

Are timber frame extensions cheaper than brick?

In most cases, yes. On a like-for-like single-storey build, a timber frame extension usually comes in around 8 to 15 percent cheaper than traditional brick and block. The saving comes mainly from speed. The frame goes up in days, which cuts the labour time you pay for.

We build timber frame extensions in Reading using a pre-engineered insulated panel system, and the difference on site is obvious. A brick and block shell is laid course by course and depends on the weather. A timber frame arrives ready to assemble, so the structure is up and watertight while a brick build is still waiting for the mortar to set.

That said, "cheaper" depends on what you are comparing. The frame itself is only one part of the bill. Once you add foundations, glazing, the roof and the internal fit-out, the gap can narrow. So the honest answer is that timber frame is usually cheaper overall, but not always by as much as people expect.

What a timber frame extension costs versus brick

Across the UK, a timber frame extension typically runs from around £1,800 to £2,800 per square metre, depending on size, finish and where you live. A comparable brick and block extension tends to land between £2,400 and £3,200 per square metre.

For a 30 square metre single-storey rear extension, that puts timber frame somewhere around £54,000 to £84,000 and brick nearer £72,000 to £96,000 at the same specification. The ranges are wide because no two jobs are the same, but the pattern holds: timber frame sits at the lower end on most projects.

A quick word on location. Here in Reading and across the South East, both methods sit towards the top of those ranges. Demand and labour rates are higher than in much of the country, so a like-for-like extension here costs more than the same build in, say, the North East.

Where timber frame actually saves you money

The biggest saving is time on site. A timber frame shell reaches watertight far faster than brickwork, which means fewer weeks of labour, scaffolding and skip hire.

Labour is usually the second largest cost on any extension after materials. Cut the build programme and you cut that bill directly. In our experience, a timber frame build can reach watertight in a fraction of the time a brick shell takes, and the whole project finishes weeks sooner.

There is also a knock-on benefit most people forget. The longer your home is a building site, the more it costs you in disruption, temporary arrangements and lost patience. A shorter build is cheaper in ways that never appear on the quote.

Where the cost gap closes

Timber frame is not automatically cheaper in every situation. A few things bring the two methods closer together:

• Brick slip cladding. If you want the extension to match existing brickwork, a brick slip outer leaf on a timber frame adds cost and narrows the saving to nearer 4 to 7 percent.

• Small, simple jobs. On a very small extension the speed advantage is smaller, so the gap shrinks.

• Ground conditions. Foundations are priced on the soil and the load, not the wall material, so a tricky plot costs much the same either way.

• High-end finishes. Bi-fold doors, roof lanterns and underfloor heating cost the same whichever structure sits behind them.

So the structure is where timber wins. The fixtures and groundwork are largely neutral.

Build time: the saving people miss

A typical 30 square metre timber frame extension runs around 9 to 12 weeks on site, against roughly 14 to 18 weeks for brick. The shell itself is the headline: 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. Bricklayers cannot work in freezing conditions because the mortar will not cure properly, so a winter brick build can stall for days. Timber frame is far less weather-dependent, which keeps the programme on track through the colder months.

For most homeowners, finishing six weeks sooner matters as much as the headline price. It is less time with builders in the garden and less time living around the work.

Beyond cost: the other things worth weighing

Price is only part of the decision. Here are the factors we talk through with every homeowner before they commit to one method or the other:

1. Insulation and running costs. Timber frame walls hit lower U-values at the same thickness, so the room is warmer in winter and cheaper to heat.

2. Internal space. Timber frame walls are thinner than a brick cavity wall, which gives you a little more usable floor area for the same footprint.

3. Lifespan. Well-detailed brick lasts 100 years or more. Modern timber frame, properly built and maintained, lasts around 80 to 120 years.

4. Appearance. Brick blends seamlessly with most UK homes. Timber frame can match it too, using brick slips or render on the outside.

5. Mortgage and insurance. Modern timber frame is accepted by every UK high-street lender, so it will not hold up a sale or a remortgage.

6. Maintenance. Timber needs good moisture management and the odd check over the years. Brick is close to maintenance-free once built.

Neither method is the right answer for everyone. The best choice depends on your budget, your timescale and the look you are after.

Planning permission and building regulations

Both timber frame and brick extensions follow the same rules. Many single-storey extensions fall under permitted development, but limits apply on size, height and how close you build to a boundary, and conservation areas and listed buildings have stricter rules. You can check the current limits on the Planning Portal before you commit to a design.

Whichever method you choose, the work needs Building Regulations approval covering structure, insulation, ventilation and fire safety. The timber frame systems we use are structurally engineered and pre-approved for Building Control, which makes sign-off more straightforward.

So which should you choose?

If your priority is a lower overall cost and a faster, less disruptive build, timber frame is usually the better value, and it gives you a warmer, better-insulated room into the bargain. If you are matching a period property in a conservation area, or you want the absolute longest lifespan and do not mind a longer build, brick still has its place.

For most extensions on most homes around Reading and Berkshire, timber frame gives you more for your money: the same finished room, built quicker, costing a little less, and cheaper to run once you are living in it. The trick is getting a clear, itemised quote so you are comparing the full job and not just the frame.