You don’t need any old timber building. You need a workshop big enough to house your bikes, tools and garden-kit with space to spare. The bigger the workshop, the more important it is to invest in high quality craftsmanship, because no one wants a workshop that’s a crumbling eye-sore at the bottom of their garden. We’re going to break down all the costs involved in a large workshop project, so you can choose a workshop that fits your needs and budget – without being blindsided by unexpected costs. 

What is a single-skinned workshop?

A single-skinned timber building is probably what you think of when you picture a traditional shed – one layer of timber makes up its walls. A lot of workshops on the market are single-skinned buildings; there’s nothing that really sets them apart from a shed specification wise, just that they’re made in bigger sizes. 

At G&M, we used to build our larger buildings, like Garages, as single-skinned constructions. But we soon realised that larger single-skinned buildings experienced more issues with water ingress. 

Water ingress is always a possibility in single-skinned buildings because timber is porous, and a little moisture getting inside is completely normal. But we found that the large boards that made up our Garages were having more issues with letting water in, compared to our smaller buildings like Sheds. 

This led us to develop our 3-Tier specification, which we now use to keep our Garages, and Workshops completely watertight. 

What is a 3-Tier Workshop?

Our 3-Tier specification is a must for our larger buildings – any building over 12’ x 10’ automatically gets built using this construction. We do this because we know that a single-skinned building bigger than this isn’t going to fare well against the Scottish weather and could eventually experience issues with leaks – and no one wants a leaky workshop. 

The 3-Tier wall is made up of:

• 19mm Tanalised Scandinavian redwood tongue & groove weatherboard cladding 
• 22mm air cavity and damp-proof membrane
• 9mm OSB structural board 
• 75mm x 45mm pressure-treated C24-grade framing

The layers of timber, in combination with the air cavity ensure that any water or moisture from outside cannot get to the interior of your Workshop. Any moisture that passes through the outer cladding is stopped in its tracks by the air cavity and damp-proof membrane, leaving the interior of the Workshop completely dry. 

If you want a large timber workshop, a layered wall with an air cavity is going to provide you with the best performance, especially in Scotland where we get so much wet weather, this is something to prioritise.  

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How much does a large single-skinned workshop cost?

The basic specification of a single-skinned workshop means that they tend to be much more affordable compared to our 3-Tier Workshops. 

Here’s a 20’ x 10’ apex workshop from Waltons, for £3,509.99. This might seem like a bargain for a building this size, but keep in mind that you’ll need to assemble it yourself and it’s always susceptible to water ingress. 

Depending on the purpose of your workshop, this kind of building could meet your needs and expectations. If you want some extra storage space, and a garden building to use mainly in the summer – then a single-skin will suit you nicely. 

But if you need a workshop that you can always rely on to be watertight, secure and last for decades to come, you’ll want to choose something with a more substantial construction.

Further Reading: Dunster House Workshop vs G&M’s 3-Tier Workshop

How much does a large 3-Tier Workshop cost?

Our largest Workshop size is a 20’ x 10’ which costs £15,825. This price includes the building itself, steel box profile roofing, a fully clad uPVC door and a horizontal uPVC window. 

VAT, delivery (within 40 miles of Errol) and assembly are also included. We cover the whole of Scotland but there will be a delivery charge outside this area.

If you’re looking for a Workshop larger than 20’ x 10’ we’d recommend checking out our timber Garages, as they go up to 6m x 5m in size. 

Further Reading: What’s the biggest wooden Garage I can have?

How much does a base cost?

A 20’ x 10’ 3-Tier Workshop needs a level and square concrete base to properly support it. If you don’t already have a base in place, we can arrange and project manage this for you. At G&M, we have several accredited trades, including our sister company CSR, who carry out base work for us. 

We will arrange for an accredited groundworks team to do a site visit, to give you an exact cost for your concrete base. A site visit is necessary to give you an accurate quote, because factors like your site access, and the amount of excavation needed, will impact the cost of the concrete base. 

A good guide cost for a 20’ x 10’ concrete base is around £4,00 – £5,500.

How much does electricity cost?

Electricity is a great addition to a Workshop as it allows you to easily power lights, heating and any other tools or equipment you need. Again, a site visit is required to give you an exact cost for electrical installation because the distance the armoured cable has to travel, and your preferences for finish, will impact the price. 

We will introduce you to, and set up a site visit with our accredited electricians RC Electrical. Then after the site visit they’ll give you a custom quote for the job. A Workshop only needs a single fit of electrics – meaning the work is usually completed within a day. 

As a rough guide, electrical installation for a 20’ x 10’ Workshop will be around £400 – £900. 

How much does guttering cost?

Another cost to think about for your large Workshop is guttering. We recommend adding guttering to your building – whether you get us to install it, or you’d prefer to do it yourself. This helps water travel off the roof without damaging the timber cladding. 

Unlike the base and electricity, guttering prices are exact, and depend on the size of your building and its roof shape (guttering for an apex roof is more expensive than for a pent). 

For a 20’ x 10’ apex Workshop guttering costs £690.

How much do windows & doors cost? 

Our 3-Tier Workshop comes with a fully clad uPVC door and a horizontal uPVC window as standard. But there’s always the option to alter or upgrade these features to suit your space. 

A 20’ x 10’ Workshop is a pretty substantial size, so additional windows, or an upgraded door is a sensible option.

The fully clad uPVC door can be upgraded to uPVC double doors for an extra £900. This is a perfect addition if you’re going to be storing large items like bikes in your workshop. 

If natural light is important, you can always upgrade the single horizontal uPVC window, for something larger:

What’s the total cost of a large workshop project?

These are two example projects, one with the basic set up that you need – the building, and a base, and another with plenty of added extras, to give you an idea of what you can get for your budget:

Remember that these are just examples, and base and electricity costs will vary depending on your specific site and needs. 

How much does a large workshop cost?

Now you know what to expect from a large workshop project you can decide whether a G&M Workshop is the right choice for you. 

For a personalised estimate for your project, try out our Price Estimator. It will take you through a few questions about your preferences and needs, and give you an instant estimate for your Workshop project. 

If you’re still unsure about costs, book a no-obligation Consultation with our Sales Team, who can offer you even more guidance about price.