Advice needed please on building a small wood workshop

[Joe1975]

I would really like to have somewhere dedicated to woodworking. There is space for a 16”x8” workshop at the end of the garden. I have a week back (herniated disc) from a previous build so need to keep the physical workload down to a minimum. With my back and the site being so far from the road I don’t want a concrete base, or even footings if I can avoid. The site is about 2’ of topsoil on a chalk bed, it is level. The build will need to be below 2.5m in height.

I have a small amount of power (effectively a 13amp socket) to power the workshop so will have to be mindful of this. I have a bandsaw and may well purchase a small table saw, pillar drill, and a thicknesser at some stage, but am mostly interested in building small pieces by hand.

I need to make sure that the workshop can maintain a dry environment - it will obviously store my wood and my tools. I guess I need some insulation and double glazing for this.

Any details on what footing/ground support would be the easiest and cheapest would be helpful. At the moment I’m thinking of digging down to hardish soil, putting a bit of hardcore in, and using stacks of heavy concrete blocks (maybe three) to about 4” above the surface. I would probably use 15 pillars on 4ft centre’s.

What’s the cheapest way to insulate the whole workshop? I want to keep the whole build down to 5-6k.

Any design thoughts especially with regards to insulation and damp avoidance would be greatly appreciated.

 

[Mel769]

Celotex insulation between studs perhaps ? Fairly cheap and available.

 

[Jameshow]

2 Concrete blocks laid flat with another at right angles would spread the load amply on normal soil.

6x2 will do for 8ft spans.

3x2 studs with 2" insulation foil facing inwards and taped. Fabric to outside, batten and cladding

Roof epm / fibreglass pro team.

 

[Ttrees]

Will Joe not have to use some form of DPM
I've been thinking the same thing with the blocks on some stone,
and it wouldn't be seen as such a permanent thing, and could be movable and cheaply adaptable
solution.
Is there a type of plastic one can do something with instead of buying a roll?

 

[Jameshow]

Best to use something Dpm under the joists or bitumen paint painted on??

 

[BucksDad]

Is it a house for life? If so could consider getting plastic joists and never having to worry about it again

 

[Daniel2]

16" x 8" is quite small by workshop standards

 

[Fitzroy]

I built a workshop on pier foundations to avoid too much potential damage to a tree root zone. The downside is height, piers finish 10cm above soil level, then with a 150mm frame you are 250mm above ground already. Place a 150mm roof on that and you’re limited to low ceilings to stay inside permitted dev rights and your 2.5m limit. For these reasons I applied for planning, was easy to do a cost about £250 and I could build what I wanted.

Damp avoidance is about good overhangs and proper wall design. See how to build a shed mikes way sticky. It’s about structure wrapped in a membrane, then with cladding to keep the rain off.

If you plan to insulate then put it in the design, don’t try to add as an afterthought. I think the easiest and most cost effective is 4x2 framework with Rockwool in between studs. Kingspan has better insulation values but is more expensive and harder to do a good job with. I’ve just finished insulating mine with 100mm Rockwool and an hour with the fan heater on took it from 5degC to a usable 12degC. Then with just me working in there the temperature would increase to 14-16degC and I’d have to crack the door to avoid getting sweaty.

I’ve ran my shed on a 13A extension lead for the last 5 yrs it’ll do any of my tools and the lights happily. No I don’t endorse this is a permanent solution, proper electrics are on the list. I have to turn the fan heater off if I’m starting a big machine else it can pop the fuse, and sometimes the cable will steam in the damp grass on a cold morning, but you pay your money and make your choice.

If you are doing the build yourself I think £5-6k is plenty for your size of building. Mine was about £3k but timber has gone through the roof since then!

Look out for free double glazed windows on gumtree and design around them to save money.

My full build is on here as a post, it’s getting a bit dated now though, especially on costs.

 

[Molynoox]

-PIR the best insulation but not the cheapest. PIR horrible to work with also
-4x2 the de facto standard for walls but 3x2 can also work if you can compromise on insulation thickness
-Pier foundations the cheapest option but you will need to excavate down first if staying under the 2.5m limit
-EPDM a no brainer option for roof imo
-Source cheap 2nd hand door and window and build walls around it - as others have mentioned

Check out ali dymok YouTube for pier foundations, and read build threads on here to get other ideas
Also, do a build thread on here and ask questions as you go

Martin

 

[Dave Moore]

You can get ground screws which can be used for piers then insulate the floor.https://pin.it/1hutyvN

 

[Joe1975]

2 Concrete blocks laid flat with another at right angles would spread the load amply on normal soil.

6x2 will do for 8ft spans.

3x2 studs with 2" insulation foil facing inwards and taped. Fabric to outside, batten and cladding

Roof epm / fibreglass pro team.

Concrete blocks
4’ centres on blocks so I think 5x2s will be fine
Happy to use 4x2 for framing
2” insulation seems to be a good compromise between cost and performance Doesn’t PIR have foil on both sides?
Fabric, batten, and cladding (ie 12mm OSB board inside only)
EPDM Roof

Thanks for the advice.

 

[Joe1975]

Will Joe not have to use some form of DPM
I've been thinking the same thing with the blocks on some stone,
and it wouldn't be seen as such a permanent thing, and could be movable and cheaply adaptable
solution.
Is there a type of plastic one can do something with instead of buying a roll?

Thank you, I had to buy a roll of DPM for another project so will use that to protect timbers at point of contact, maybe bitumen paint would be belt and braces. It’s possible damp leaves may accumulate underneath.

 

[Joe1975]

Best to use something Dpm under the joists or bitumen paint painted on??

Will do, thanks

 

[Joe1975]

Is it a house for life? If so could consider getting plastic joists and never having to worry about it again

House for at least another 10yrs, but I want it to last. I think treated 5x2 timber that are not exposed directly to moisture should last a while, don’t you?

 

[Joe1975]

16" x 8" is quite small by workshop standards

Yes, one end will be a workbench, with a tool cabinet on the wall. The other end will be for a bandsaw, small table saw, and wood storage. Of course it would be nice to have more space, if things get serious I will need more power as well.

 

[Joe1975]

I built a workshop on pier foundations to avoid too much potential damage to a tree root zone. The downside is height, piers finish 10cm above soil level, then with a 150mm frame you are 250mm above ground already. Place a 150mm roof on that and you’re limited to low ceilings to stay inside permitted dev rights and your 2.5m limit. For these reasons I applied for planning, was easy to do a cost about £250 and I could build what I wanted.

Damp avoidance is about good overhangs and proper wall design. See how to build a shed mikes way sticky. It’s about structure wrapped in a membrane, then with cladding to keep the rain off.

If you plan to insulate then put it in the design, don’t try to add as an afterthought. I think the easiest and most cost effective is 4x2 framework with Rockwool in between studs. Kingspan has better insulation values but is more expensive and harder to do a good job with. I’ve just finished insulating mine with 100mm Rockwool and an hour with the fan heater on took it from 5degC to a usable 12degC. Then with just me working in there the temperature would increase to 14-16degC and I’d have to crack the door to avoid getting sweaty.

I’ve ran my shed on a 13A extension lead for the last 5 yrs it’ll do any of my tools and the lights happily. No I don’t endorse this is a permanent solution, proper electrics are on the list. I have to turn the fan heater off if I’m starting a big machine else it can pop the fuse, and sometimes the cable will steam in the damp grass on a cold morning, but you pay your money and make your choice.

If you are doing the build yourself I think £5-6k is plenty for your size of building. Mine was about £3k but timber has gone through the roof since then!

Look out for free double glazed windows on gumtree and design around them to save money.

My full build is on here as a post, it’s getting a bit dated now though, especially on costs.

Thank you. Did you not use OSB on the outside of the studs as well as the inside?
Is the breathable membrane (TYVEK Housewrap) strong enough to hold in the rock wool?
It sounds as though the rock wool works well.
I will look out for secondhand windows and door.

 

[Joe1975]

-PIR the best insulation but not the cheapest. PIR horrible to work with also
-4x2 the de facto standard for walls but 3x2 can also work if you can compromise on insulation thickness
-Pier foundations the cheapest option but you will need to excavate down first if staying under the 2.5m limit
-EPDM a no brainer option for roof imo
-Source cheap 2nd hand door and window and build walls around it - as others have mentioned

Check out ali dymok YouTube for pier foundations, and read build threads on here to get other ideas
Also, do a build thread on here and ask questions as you go

Martin

Thank you, Ali Dymock’s series is very thorough but a bit higher spec than I was planning for this build. Trying to work out where I can reasonably cut corners and expenses.

 

[HOJ]

16" x 8" is quite small by workshop standards

Doll's houses are bigger!!

 

[Jameshow]

Doll's houses are bigger!!

" = Inches
' = Feet.

 

[Fitzroy]

I have OSB outside the studs, it is not ideal with an insulated structure as you risk a condensation trap. However the Canadians will tell you they’ve done it that way forever.

I’d not thought about if externally just having house wrap would hold the Rockwool adequately. With the battening you’ll require for the external cladding the house wrap is held pretty tight and it’s pretty robust fabric so I’d say it’ll be fine. The Rockwool slabs have quite a bit of structure to them.