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Looking to buy a Garage?
Well, our sheddie friend, you want to take a look at our Buyers' Prep Guide – from planning permission, to site access, base work, aftercare and more, in this guide you'll find everything you need to know about ordering your very own G&M garage ❤️

What kind of base do you need for a Garage?

Garages don’t have floors, so they need a concrete plinth to sit on. This is where most people who are thinking about buying a Garage start to ponder.

“Okay so I want a Garage, but I need to have a base first…”

Oh, Shedlord – what now?!

Well, the plinth needs to be strong enough to carry the weight of the walls and the roof, as well as whatever you’d like to put in it.

It also needs to be a certain size, made from the right stuff, be in square and BANG ON level.

Not asking for much right?

Way back, in the beginning, Garage bases were always a nightmare to organise. So bad in fact, we had to start making them ourselves.

Ludicrous! A joiner making a Garage base? Yep. It happened.

Please note: We highly advise you obtain landscaper/construction quotes for base work before ordering your Gillies and Mackay building to obtain a full and clear picture of project costs.

Three things we know about Garage bases

1. Excavation

If your existing site is MENTAL unlevel, you have horrendous access and a terrain soft as butter, then it’s going to take a lot of preparation before we get anywhere near the concrete.

If your Garage is where ‘normal’ people have their garages, to one side of the house, already level AND in good standing firm ground, then you can put the kids’ university funds away! We’re going to have an easier ride here.


2. Sub Base

Once the area has been excavated we’ve got some serious jobs on.

Depending on the ground condition you can expect to lay a minimum depth of 100mm of T1 hardcore. Once this is compact and level you would lay a DPC (damp proof membrane) before the concrete gets poured.

G&M Garage Base Specification

3. Concrete

I like to call this the list of three to concrete perfection:

  • To Size
  • In Square
  • Level

Not all base layers appreciate our method. Some like to make the base bigger than the Garage.


Don’t do that.

To Size

Before concrete is poured there’s a timber frame built to shutter the concrete in – this is where the measurements are so CRUCIAL!! Setting up the formwork takes precision and close attention to where you’re measuring from.

If your base is not to size then we cannot slot the walls over the sides allowing the water to drain away from the building properly.

In Square

Keeping your base ‘in square’ keeps the building in square. How you do this is by using the corner to corner measurements.

Finally… a use for all that geometry you learnt at school! The square is imperative to how the building goes together. If your base is not square, Calum will have to ‘THROW’ the panels which isn’t nice to see, nor is it a pretty finish.


Some base layers cannot fathom the prospect of not having a ‘run’ on the level. A run on a base is typical to allow water to run away. Our Garages do not want a run because they don’t leak so there’s no water. This is common on hard landscaping but is definitely not welcome on a garage base.

LOOK?! Isn’t she beautiful?

Stunnin’ Concrete Base

Now I know what you’re thinking… I cannae do that?!

You’re right, so please, for all the Shed love in the world, do not try it – unless, of course, laying concrete is your actual job.

Who do G&M recommend for your Garage Base?

At G&M we only work with amazingly handsome and clever trades. Thankfully we have a whole list of accredited contractors to kit you out with a magnificent Garage base.

We would LOVE to give you an accurate price for a Garage base, but like most important things in life, it’s complicated. So complicated that we have a whole blog on how much a Garage base costs. It breaks down exactly what’s involved in the process and how this impacts the price.

Some of the factors which affecting the price of a Garage base are:

  • Access to the work area, if this is awkward with maybe poor access for equipment and machinery.
  • Removing excavated spoil from your site.
  • If the existing site is not level, additional hardcore may be required.
  • If your contractor isn’t local there may be travelling costs and overnight accommodation to add.
  • Ducts for services would be a small additional cost.

The golden rule with a Garage base price is to have a contractor carry out a site visit and give you a quotation. There shouldn’t be any charge for this service, and this will give you a clear indication of the price for your individual project.

So, there you have it Sheddies! A Garage is only as good as the base it stands on – so be sure to get it right.

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