
(Under 12m2) Specification
This article is about our former summerhouse specification, which has since been replaced by our brand-new Garden Rooms (under 12m2). It's worthwhile reading, but to jump straight to learning more about the new spec, click on!
For over 30 years, summerhouses have been the pinnacle of the G&M product range. Your careful purchases meant that summerhouses formed 80% of our sales. However, over the past three years, we have seen a rapid decline in our single-skinned summerhouse sales as the demand for insulated and double-glazed Garden Rooms has boomed.
A decline in sales means that we’re not giving you what you need. This is something we take very seriously indeed.
So we paid close attention, listened carefully to your feedback, and discovered several problems that we committed to solving.
Problem: Summerhouse Maintenance

Some timber buildings need more of your care and attention than others. To get the best from a single-skinned summerhouse you have to ventilate the building regularly, take steps to eradicate moisture, and devote time and energy to keep your summerhouse well-maintained.
If you’re happy to do this, no problem. Your regular TLC will counteract the natural behaviour of timber when it’s exposed to moisture, and your summerhouse will be solid for decades to come.
But if you don’t stay up to date with maintenance, windows and doors shift and stick, window seals fail and let water in, mould forms inside, and the building needs multiple visits from us to keep it in working order.
What was our conclusion?
More and more we found that the ongoing maintenance was something you didn’t want to do. Who needs another job on top of the ever-increasing pile of jobs, right? Your expectations increased in terms of how the building functioned which resulted in increased frustrations for you and more time and cost for us to get out and help.
Problem: Mismatched Expectations

Whether it’s the performance of the building or value for money, mismatched expectations are no good for anyone.
High-quality garden buildings are a big investment and it’s disappointing when you can’t make the most of that investment because of the weather. And let’s face it, we’re all ruled by the weather in this part of the world.
Sitting in your summerhouse on a warm sunny day is a delight. But how many warm sunny days did we have this year?
There’s nothing worse than finding that you can’t use your summerhouse because it’s too cold, too wet, or even occasionally too warm.
You want a building that’s comfortable, useable and a return on your investment all year round.
This mismatch of your expectations and the limitations of the summerhouse specification leads to disappointment, hassle, and time and energy expenditure that you don’t want or need.
Solution: Upgrade the specification; eliminate the problems.
Experience has told us that when a building’s specification improves, all these issues disappear.
Let’s look at our Garages as an example.
We stopped making single-skinned Garages in 2016 because we were completely scunnered with water ingressing through the walls. The last thing you wanted was a soggy Garage, and the last thing we wanted was disappointed Garage customers.
It was a quick decision to make the Garages 3-tier even though doing so tripled the price of the buildings.

We stopped making side-hung barn doors also, as they continually had movement issues. Now we only fit Hormann garage doors courtesy of Tayside Garage Doors.
Because of these changes, our Garage customers receive a superior product that never needs a return visit. Garages are now our leading product because we went for better rather than cheaper.
A similar thing happened with our Garden Rooms. We used to make our own double-glazed windows and doors for them. This was short-lived, however, as we kept having issues with failed double-glazing units and movement.
To address this, we have been using uPVC windows and doors exclusively since 2017.
So, what we’ve learnt from our two most successful products is that better is best. When we try and compete on price we always fall short of what is most important to us: quality.
Problem: Finding a high-quality garden room at an affordable price.
The garden room market is booming. However, both the market and its customers suffer from an abundance of cheap, poor-quality alternatives.
From composite-clad ‘insulated’ buildings to southern European interlocking log cabins, these cheaper alternatives fall within the £5,000 – £15,000 price bracket, and are totally unsuitable for withstanding the Scottish climate.
But compared to a single-skinned G&M summerhouse, no matter the pitfalls with these poor-quality garden rooms, customers have of course favoured the insulated and double-glazed buildings, which seem at face value to be lower maintenance.
You were left with the choice of a more expensive building or a poor-quality building. In other words, more disappointment and more frustration.
But we are Gillies & Mackay, and if there’s one thing we know it’s how to make buildings better.
Solution: Combine a summerhouse upgrade with an affordable garden room specification.

To solve this problem, we’ve updated our single-skinned summerhouse specification to offer you market-leading insulated and double-glazed small Garden Rooms.
While these small buildings fall into the same price bracket as those disappointing alternatives, they absolutely blow them out of the water when it comes to quality.
What can you look forward to seeing in our new-specification Garden Rooms?
Double-glazed windows and doors.
You love our petite, beautiful summerhouses. They’re small, perfectly formed buildings.
That’s why we’re keeping four of your favourite summerhouse designs. And the last thing we want is to detract from their appearance.
So while uPVC windows are excellent for larger Garden Rooms, putting 70mm thick layered plastic frames into these smaller builds would be a sin!
To maintain the refined appearance of the buildings, we’ve chosen aluminium framed units. If that’s what you’re going for, you might as well double-glaze them too.
We are not a sash and case manufacturing company, and we do not have the machines and technical ability to achieve the precision we’d like in our windows and doors.
So instead these window units come to us from a specialist manufacturer in Fife. They’re pre-glazed and fully finished – machine-made to our size and specification, perfect for slotting into our legacy designs.
Finally, you can have the double-glazed windows and doors your building deserves!
Thermally-treated Radiata Pine cladding
How do we deliver you the most reliable timber building possible? Well, that was tough.
The first issue is the timber quality from the Scandinavian pine we use. Despite sourcing the highest grade of pine available, it’s still not good enough.
Now call me a conspiracy theorist if you like, but it used to be good enough. It used to be our pride and joy, but ever since Brexit we just never seemed to get back to the good stuff.
So, if we can’t get what we need to give us confidence in our wood from the Arctic Circle, then where do we go? Siberian Larch is out of the question.
The next level up from that would be ThermoWood – specifically Radiata Pine. And through much deliberation and almost 5x the cost we confirmed: better is best.
That’s the cladding sorted. But it still doesn’t solve the water ingress issue, so we must create a cavity. This is the key to our Blackstone Garden Rooms, the large, custom-built option that starts at around £18,000.
If that’s your budget, and you’re looking for a fully Building Control-compliant Garden Room fit for living in, our 5-layered wall structure will give you exactly that.
But if you want something smaller for a dedicated space – office, crafts, music, train set, recreation, whatever – our new specification is exactly what you need.
Triple-layer cavity wall structure.
Because these buildings are under 12m2 they don’t require five layers. They can function and perform to your expectations with three layers.
With that all-important air cavity, water ingress is no longer an issue. Insulation and lining create a building that is warm in winter, cool in summer, and dry inside all year round.
And of course, there are a few innovative trade secrets to combat moisture that you’d only learn if you were to crack open a new spec Rannoch, Vorlich, Kindrogan or Deuchny.
Some things are better kept in the family!
Will Gillies & Mackay still build Blackstone Garden Rooms?

If you’re looking for insulated and double-glazed Garden Rooms that are under 12m2, our new specification is perfect for you.
If you want a Garden Room larger than 12m2, you need a Building Control-compliant Blackstone Garden Room.
Above 12m2 the building must be engineered differently to ensure it is structurally sound. That’s where the 5-layer specification comes in.
We can’t use our new 3-layer specification for these larger Garden Rooms, but for smaller buildings, we’re giving you the best of both worlds.
A top-quality Garden Room that won’t break the bank.
To Our Existing Summerhouse Owners:

You’re the owner of a top-quality single-skinned summerhouse from Gillies & Mackay.
We’re confident that our summerhouses are superior to those that you find on the Scottish market in regards to construction and materials used. We’ve been talking about it long enough and investigating the market long enough.
As we’ve always said – they will require maintenance to reduce common timber challenges such as mould and timber movement. If you take care of it as per our Aftercare instructions – it can last you a lifetime.
The functionality of a summerhouse has always been to use as a seasonal building during spring and summer and if that’s what you’d like to continue to do, that’s fabulous!
If you’d like to upgrade and get more from your summerhouse and convert it to a garden room, reduce the common jobs and maintenance required – then we will be offering upgrades of lining and insulation and double glazing in Spring 2024. (Conditions apply)
But the wonderful thing about ShedLife is that it’s different for everyone and it moves with you. We’re not leaving anyone behind. Instead, we’re opening up our next evolution of timber buildings.
Bidding a fond farewell to single-skinned Summerhouses.

Summerhouses have served us well. But just as VHS turned into Netflix as technology improved and demand shifted, our new specification is an inevitable design evolution.
It’s time for us to say goodbye to single-skinned recreational buildings. Insulated and double-glazed garden rooms are the way forward.
We are so excited about what this means for our future and for yours.
For us, there will be no more adjusting doors, re-sealing windows, dealing with disappointment in Storm Babet, and no more STOCK BUILD!
For you, we’re delivering a market-leading product designed and created with 30+ years of experience in the best timber buildings around.
We can’t wait to see what you do with them!
If you’d like to learn more about the Garden Rooms, what they look like and pricing – head here.