By Amy Hanlon on 05 Sep 2023
Sheddies, we do our best to give you all the information you need to make good choices about garden buildings. Do you want to know about plastic sheds? There’s a blog for that. Wondering what kind of summerhouse you can get for £2000? We’ve got your back. Our Learning Centre has posts on every aspect of buying a shed, summerhouse, garage or garden room. But when it comes to answering the question “How much does a garage base cost?” we’ve struggled a bit.
Not because we’re slacking, or because we don’t want to tell you. The reason this question is so difficult for us to answer is that WE DON’T KNOW. We don’t build garage bases. If you’re buying a garage, we put you in touch with one of our accredited trusted contractors. They’re the experts who come up with your quote.
So, when Cara said, “Right! People need to know how much a garage base costs – get to it, Amy!” the sensible thing for me to do was to ask someone who builds garage bases.
Because while you can use a slab base for a shed, a garage needs a poured concrete plinth. Perfectly flat, totally square, exactly the right size. I needed to talk to a specialist.
D&G Specialists
And that’s exactly what I did. Greg at D&G Specialists was good enough to give me the information I needed to answer your question.
Greg told me how his firm prices garage base quotes. I still can’t tell you how much YOUR garage base will cost. Greg and his guys would have to see the site of your building to determine what needs to be done.
BUT… I can help you understand how a poured concrete plinth is made, and show you what you’re paying for.
To do this, I’ll show you a quote that Greg’s firm drew up for one of our customers this year.
What costs are involved when building a garage base?
The two main things that you pay for when you have a garage base built are materials and labour. Neither of these things comes cheap. If you skimp on the quality of your materials, you run the risk of having an inferior base. The labour involved in building a concrete base can be considerable even before you start thinking about experience and expertise. The last thing you want for your garage is a sub-standard base. Make sure you hire someone who knows what they’re doing.
How do materials contribute to the cost of a garage base?
Part of the reason that garage base prices can be so elusive is that every project is unique. If you’re building a small timber garage you need more concrete than if you’re building a large timber garage.
Also, the cost of concrete has risen dramatically over the last few years and continues to fluctuate. This situation is out of your groundworks firm’s hands – if concrete prices rise, so do their quotes.
As well as the concrete itself, your base will also need:
- Type 1 hardcore (to form a layer minimum of 100mm thick).
- Blinding sand (placed on top of the hardcore to level it and protect the damp-proof membrane from any sharp stones).
- A damp-proof membrane to cover the entire base area.
- A252 mesh reinforcement to strengthen the concrete.
- A timber form to pour the concrete into.
How much does labour contribute to the cost?
Building a garage base is a hard graft. There’s digging, dumping and concrete laying, as well as for transporting everything they need to and from the site.
One factor that affects labour costs is site access. A garage at the end of a gravel driveway with easy access is one thing. A garage at the bottom of a mile-long dirt track that only allows access for a Mini is quite another. This is why a site visit is a crucial part of the process.
When Greg comes to see the proposed site of your garage, he needs to consider the following things:
- What’s the site access like?
- How much excavation will it take to level the site?
- What type of ground needs excavated?
Why does my site access affect the cost of a garage base?
Garage bases involve excavation, or digging. If you or I dug a hole, we’d probably start with a spade and get the job done eventually. However, professionals like D&G Specialists use an excavator, which is a mechanical digger. This does the job much faster and much more easily.
If your site access won’t allow a digger in, the labour costs for your garage base will be considerably higher. The excavation will have to be done by hand, meaning more hands are needed and the job will take longer.
Site access also affects the labour required to bring in the materials needed for your base. To achieve the smooth, perfectly flat finish needed for a garage base, the concrete is poured quickly once it’s mixed. If the concrete can’t be mixed close to the site, the contractor will need a pump to transport it. The cost of hiring any special equipment will also be added to the cost of your project.
Why does the amount of excavation needed affect the cost of a garage base?
Whatever equipment you use, the amount of excavation needed impacts the amount of time and labour required. If you’re lucky, you’re starting with a relatively flat site. If you’re on a slope, more cubic metres of earth need to be removed to create the flat site needed. This will be factored into the cost of your base.
Why does the type of earth being excavated affect the cost of a garage base?
Earth, soil, dirt, ground – whatever you want to call it – might be soft and regular and easily moved. It might be compacted solid and full of hefty rocks that need to be dug out by hand. It can also be too soft, which means more digging and reinforcement. When Greg conducts his site visit, he does his best to estimate how much excavation is needed. But until his team starts digging, they have no idea what sort of ground they’ll be working with. Excavation can take longer than anticipated if the ground is hard to work with.
Which other factors contribute to the cost of a garage base?
Is there anything else that you haven’t thought of? As well as the materials and labour, the following jobs may be necessary:
Disposing of waste
The more digging that has to happen to level your site, the more waste you’re left with. If you have a skip or somewhere on-site to dispose of waste, this will cost less than moving it off-site. The additional cost of transporting and disposing of any excavated material also forms part of your quote.
Extra concrete to form a ramp
If you need a concrete slope at the front of your garage you’ll also see this included in your quote – both the materials and the labour involved. This provides easy access to the garage without having to bump your car up a step. If you’re not using your garage to store a car, you may not need this. I
Upgrading existing foundations
If you already have a base, it may still need work to make sure it meets our very high standards. Existing foundations are the same. Our contractors know what they’re doing, and sometimes that involves upgrading existing work. This makes sure that your garage base is totally solid.
Is VAT payable on a garage base?
It is indeed. Contractors charge VAT at 20% of the cost of materials and labour. Make sure you’re clear about whether any quotations include VAT or not. Quotations often don’t include VAT, and no one wants an unexpected shock when it’s time to pay the bill!
How much does a concrete garage base cost?
This is all very well, but where are the numbers?
The numbers don’t really make much sense if you don’t consider these factors. Remember – every project is different.
Let’s have a look at the quote that D&G Specialists gave our garage customer. Included in the job is:
| GARAGE BASE | |
| Excavate to reduce levels | 16m3 |
| Backfill trenches with arisings | 1m3 |
| Dispose excavated material off-site | 15m3 |
| Upfilling base with imported hardcore | 8m3 |
| 50mm sand blinding | 35m3 |
| 1200 gauge DPM | 35m3 |
| Supply and place 150mm thick Grade C32/40 concrete floor slab; floated finish | 35m2 |
| Extra over for forming slope at doorway | 3m |
| A252 mesh reinforcement | 35m2 |
| Formwork 150mm high | 27m |
| TOTAL: £9,278.54 | |
| TOTAL + VAT: £11,134.25 | |
This quote is for a 34.3m2 garage. The size of the garage means that the largest cost was for the concrete, followed by the formwork. Greg’s team needed to carry out a whole lot of excavation. The cost of materials was significant even before taking the labour into account.
You can see that this quote accounts for all the parts of the project. The customer ended up with a beautiful floated base, ready for their glorious G&M garage, and Greg’s team removed all the excavated materials.
But sometimes base quotes are significantly more and significantly less than this quote. It’s not as simple as calculating the size of the building and working up from there.
How much does a garage base cost per square metre?
I also looked at a range of base prices that our garage customers have paid over the past year (2022-2023). Based on these, the price per square metre for a concrete garage base ranges from around £250 to £420.
This price range includes D&G Specialists as well as the other contractors we recommend. D&G’s quote works out at around £320 per square metre. However, I’ll say it again. Until a contractor surveys your site, you won’t know where your base will be within that range. It depends on so many other factors.
Can I get a bargain on a concrete base?
Sometimes you can. However, there’s a reason that we recommend contractors. The experience and skill required to pour and finish concrete is a crucial part of the success of your base. A successful base means a successful garage. If this was an easy job, anyone could do it.
If you’re shopping around to try and find a bargain base, try to find an established contractor. Ideally, get a look at some of the work that they’ve done previously. Recommendations from a trusted party are best, because unless you’re an expert, you may not be able to tell the quality of the work.
Make sure to ask your contractor exactly what they’re quoting for and make sure that they follow our specifications. Look at the quality of their materials as well as their experience.
Once you’ve found a price for your base – what are you waiting for? Get cracking with that gorgeous garage! Remember – you can come and see the timber garage in our Show Area (complete with concrete base!) And if you’re ready to talk to the Sales Team about your dream garage, they’re right here.
More reading:
Why our garages don’t leak: the best timber garage specification.
