New Workshop build.....not for what you'd expect though...

[Andyguk]

Hi all,
I'm new to these forums but I've been following them for a while and find them a mine of inspiration, a great resource for everyone.

I'm now in the position of being able to build my ultimate workshop, not for woodworking or construction though (that workshop will come later on the other side of the garden ) this is to house my exhibition standard o gauge model railway layout, see below.

I've removed an old oil tank installation and dilapidated shed and rebuilt the boundary wall and fence and installed a fireproof bunded Tuffa oil tank so I can build within close proximity and adhere to all regs. The workshop will be 'L' shaped in order to maximise space usage without obstructing our garden views too much whilst still enabling the layout to fit with adequate space for an airbrushing booth, workstation,etc. (I've modelled this up parametrically in 3D on a CAD package to ensure everything fits ok, so I'm quite happy with the overall design with respect to size and position). The workshop is 21 feet long by 10 feet at it's widest point so fits under the size where planning/building regs come in due to it's position and height meeting all applicable requirements (I have also talked this through with local offices to confirm just to be on the safe side).
Due to the variance in ground level where I'm building I'm going to go along the route of laying a boundary wall up to plinth level in order to facilitate ease of levelling, backfilling and eventual pouring of concrete base plinth. I just wanted to get some feedback on this and have attached a mock up in 2D of what I intend to do. Cost is not really a problem as this will be a long term building so I'd rather not cut corners and need it to be dry and warm all year round.
Let me know what you think....

Cheers, Andy

 

[MickCheese]

Have a look at this.

https://www.ukworkshop.co.uk/forums/build-a-shed-mike-s-way-t39389.html

Mick

 

[carlb40]

Your plan for the floor is almost correct. However there is no need for the 2 DPM layers. The first on over the sand will suffice as long as you bring it up to the damp level.

Look forward to the build

 

[Andyguk]

Ah, OK. So you reckon take the 1200 gauge under the concrete pad and instead of turning it down to meet the layer under the foundations, turn it up and take it up and tuck it under the DPC, then don't bother with the layer under the kingspan ?

Anyway, here's the CAD mockups I drew up, still a work in progress but you get the idea...

 

[Andyguk]

Clearing out the site....

 

[Andyguk]

The excavation commences....

 

[Andyguk]

Base is now done...timber arriving next weekend

 

[longinthetooth]

You appear to have incorporated an uninsulated masonry upstand - why?

 

[Andyguk]

The photo's a little misleading due to the excavation of the existing block paving, when the ground level is reinstated the near end will only be 100 mm above ground level, the height is required due to the slope of the garden dropping down by around a foot or so. If you look at the CAD section at the start, you can see how I plan to insulate it. I thought about insulating the slab, but as it'll predominantly be used for short periods of time, insulating above the slab will allow for a quicker warm up time for the interior, ideal if I want to pop in for half an hour when I can grab the time.

Cheers

 

[Andyguk]

...and the other reason being that beyond my back fence is twenty miles of countryside, hence a well built masonry base will stop every rat or field mouse in the vicinity gnawing their way in !!

 

[longinthetooth]

No, Andy, sorry - I was looking at the drawing - you've shown no insul on the stub wall, making it a thermal bridge ...

 

[Andyguk]

That's the way Mike Garnham recommended which seemed to be the generally accepted blueprint for a successful workshop build around here.

build-a-shed-mike-s-way-t39389.html

For me, having the bottom 8 inches or so of the walls in block work appealed for the reasons above plus raising the timber sole plate and structure up away from the ground. Not sure how much heat loss will occur here, but definitely open to suggestions of any improvements, thoughts everyone ???

Cheers

 

[devonwoody]

I am sorry I cannot advise you on construction of building but I am interested in your project, (model railway enthusiast), do you post on a model railway forum?

I used to visit Pendon in days gone by and you yourself appear to be a dedicated modeller.
Please keep posting, I and others I am sure are very interested.

 

[longinthetooth]

Yes it's good to raise the timberwork above the ground into a dryer environment away from splash-up, for its longevity.

My point was purely a thermal one. You have shown an uninsulated course of blockwork. I'm assuming a heated space (why else insulate?), and in that circumstance the stub wall as shown will lead to (1) heat loss, (2) condensation on its inner face & (3) resultant mould etc.

 

[Andyguk]

Yep, good point. Not sure whether this has been a problem for anyone following these guidelines, but thinking about it, the possibility of condensation and mould on this portion of wall could be a concern. What I could do is put a thin layer of kingspan on ths stub wall bridging up to the top of the sole plate with the vapour barrier covering it down to the floor, then ply over the front and a horizontal batten to connect it back to the inner wall ply. Sort of like an extended insulated skirting board.
Hopefully that should give me the best of both worlds, masonry lower lifting the timber clear of the ground plus full unabridged insulation. What d'you think ??

Devonwoody, I post on RMweb, plus there was a feature article on my layout in the January edition of the railway modeller if you're interested. I'll definitely keep posting as this forum has been an invaluable source of info and hopefully my stumbling efforts may prove useful info to someone else down the line

Cheers

 

[longinthetooth]

Yes Andy, you're on the case! You've even thought of the vapour barrier. If possible I would take the kingspan up a little higher so that it laps beyond the soleplate to reduce thermal bridging at that point.