DIY Garden room cost – Real life example

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In this article, we will be looking at the cost to create a DIY garden room by yourself. This will focus purely on the cost of materials, and we will be looking at a DIY garden room that I recently completed.

The garden room I am referencing throughout this article can be seen below, and it is roughly 3X4m in size. However, because other people will be building in different sizes, I will also include average prices per m2.

diy garden room cost

In total the DIY garden room cost was £7457.07 + £100-£200. This extra amount includes some fixings, adhesives, and sealants that I already had, so I didn’t need to buy them.

Based on this, the average DIY cost per square meter was roughly £638.

The DIY route is definitely cheaper than hiring someone to do the work. In comparison, when hiring a professional, the average cost in the UK is around £2000 per m2. This will also vary based on several factors, which could see prices range from £1500 – £5000 per m2.

Based on the average of £2000, the cost is around 1/3 if you do the work yourself. However, there are several things you need to consider:

  1. It will be hard work
  2. There is a certain amount of skill and knowledge required
  3. You will need to spend time finding the best deals on materials and trades such as your electrician.

It’s also worth noting, that I decorated and plastered everything myself. If this is something you plan to outsource, this will add extra expense.

DIY garden room cost break down

Below is a rough breakdown of the total materials cost:

  • Materials to form the concrete base construction – £383.18. This included ballast, cement, hardcore, hiring a mixer, and buying timber to create the formwork.

  • Timber to construct the walls floor and roof – £1051.03. This was a mixture of 3×2, 4×2, and 5×2. It also includes structural OSB, that was fitted externally to the walls and roof timbers. As well as weather protected tongue and groove flooring, to form the sub floor.

  • Insulation – £502.61. The insulation was all PIR insulation (mostly Celotex) this was 50mm in the floor and walls and 100mm in the roof.

  • External breathable membrane and battens for cladding – £123.66

  • Facia, soffit, guttering, and rubber roof – £861. This was all purchased online, and the rubber roof was a full kit that was delivered ready to fit, including everything needed to complete the job. It also includes guttering, downpipes, and a water but.

  • UPVC doors and window – £1256.99. These were relatively cheap options that I bought online, and I am very happy with them.

  • Cladding and oil finish – £1589.95. The cladding I used was a British western red cedar and this was finished with Osmo UV protect oil. Whilst this was a big expense, the British cedar is significantly cheaper than Canadian red cedar.
  • Plastering and painting – £391.24. This includes adding a vapour barrier, tapered edge plasterboard and drylining. This was followed by skirting boards, and everything painted.

  • Electrician – £1033.81 – The electricians cost included labour and materials, so this included all the wiring, sockets and switches, downlights, etc.

  • Rubber gym flooring – £263.60.

As I mentioned previously, there may be a few small additional expenses for some miscellaneous items. This will include things like screws, nails, and adhesives, but I would be very surprised if this was over £200.

Things that could affect your garden room cost

The costs listed above are a pretty good guide for this type of project. However, there are several things that can influence the price.

One thing that will affect price is the quality of materials. This is mainly related to things like you’re cladding and your windows and doors.

For example, the cladding I used cost £1495.45. However, if I wanted to use a Canadian western red cedar (which is very popular for this type of project), the price would have been over £3000. Similarly, if I wanted to downgrade the quality, I could have bought a treated softwood cladding from my local builder’s merchant.

The Canadian cedar does give a very premium look. Whereas the cheap treated cladding would be the type you would use on a shed. Therefore, I believe the British cedar was the most economical option. It still looks great and is significantly cheaper than the Canadian cedar.

When it comes to doors and windows, I chose to fit UPVC. Had I chosen composite or aluminium, the price could have been significantly more.

Aluminium bi-fold doors are very popular with garden room companies, and they do look great. However, they are not cheap, and this could have more than doubled the price of my doors.

As you can see, just increasing the spec of the cladding and doors could have added £3000-£4000 to my overall cost.

Ways to reduce DIY garden room cost

Whilst increasing the specification can raise cost, there are still ways you could reduce costs lower than my project. Below are a few ideas:

  • Buy second hand doors and windows – There are always old windows and doors listed on sites like eBay and Facebook marketplace.

  • Search Facebook marketplace for other materials. Builders, other trades, and DIY’ers often over order and need to unload some excess materials. Because these items are local, you can easily pick them up and they will often be heavily discounted (sometimes even free).

  • Choose cheaper insulation – PIR is the most convenient, but it is not the cheapest. Rockwool is another option to consider, and it is definitely cheaper.

  • One of the main things that will have an impact on price, is the cost of materials and labour. You can save money by shopping around to find the best prices.

    Materials will be significantly cheaper if you buy from local builders’ merchants, as opposed to the big public DIY stores. Also, if you are hiring tradesmen, comparison sites can result in big savings.


DIY garden room costs can be affected by a wide variety of factors. However, it is considerably cheaper than hiring a professional garden room company. So now the real question is are you confident you can do the work?

The best way to build this kind of project as a DIY’er, is to use plans created by someone who has already done the job. Or alternatively you can watch someone else building a garden room. You can actually watch my entire build on YouTube by clicking here.

I hope this article has given you a good idea of the price you can expect to pay, and good luck with your own garden room project.

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