What is the Best Timber Garage Specification

I’ll say this quick, so as not to cause alarm… A single-skinned Timber Garage draws moisture from the air and passes it through its walls to the inside. It’s not leaking, it’s ingress.

But what if you don’t want it to do that? What if you want the inside of your Timber Garage to be nice and dry? How do you stop it from passing moisture through to the internal part of the structure?

Well, as you know, in Scotland, we get a whole lot of rain… in fact, it’s been raining for a while, maybe 4/5 billion years or so (slight exaggeration). But nothing like the past 3. It’s been relentless.

So, what we’ve had to do, is come up with a new plan! A three-tier wall construction that laughs in the face of water… ha!

And it looks something like this…

Contents

Cross Section – 3 Tier Timber Garage

The Wall Construction for a Timber Garage

19mm thick tongue and groove pressure treated weatherboard – Pressure treating the cladding protects it against rot for over 15 years but we always recommend that you paint it to see the wood lasting many years more.
22mm pressure treated batten – This is what creates the cavity… Water can do a lot of things but jumping 22mm with no propelled effort is beyond conceivable – however, just to be sure…
Breather membrane – This membrane acts a barrier from the outside to the inside and stops any moisture from the external cladding, protruding into the internals.
9mm OSB sheeting -OSB or oriented strand board is – waterproof adhesives that bond the wood fibres together creating strength and excellent load bearing properties.
95mm x 45mm pressure treated framing – Our framing is C24 graded – meaning it’s really strong and can withstand the weight it must carry plus any additional loads. weather or human permitted.

The Roof Construction for a Timber Garage

95mm x 45mm pressure treated framing [minimum size]
16mm tongue and groove sarking treated with Anti-Fungal wash – We like to use the tongue and groove 115mm wide boards because of its bracing qualities.
22mm pressure treated batten
Proctor Roofshield membrane – This provides a secondary barrier to the ingress of rain, wind and snow. It has a low vapour resistance and is air-permeable; additionally, it eliminates the incidence of condensation in pitched roofs.
0.5mm Polyester coated steel box profile sheeting [20-year guarantee] – Steel Box Profile is brilliant, reliable and durable. It’s so good I’ve done a whole blog on it; Do I need a Steel Box Profile Roof on my Shed.

We make our Timber Garages in sections in the workshop and then assemble them like a massive jigsaw on site. We introduced this new Garage specification in 2016, but we’ve been doing it for years with our Cabins so we know it works.

It’s so good when things just work don’t you think?