New workshop build

[ollied1981]

Hi,
First post on here, great forum I must say. Thought I'd post some pictures of the new workshop I'm building. I'm more into metalwork than woodwork but the building is mostly wood so I reckon it qualifies for this forum

So far I've made a reinforced concrete slab over a DPM and the 4x2 timber frame. The plan is then to sheath in OSB, Tyvek or similar then cladding over battens. The roof will be 18mm OSB covered in EPDM.

The external dimensions are 3.5m x 3.5m x just under 2.5m high. I've got a used plastic door and windows as thought this was easier than making them!

As a second step I want to fill the walls out with some kind of insulation and board out the inside. Considering moisture resistant plasterboard because I might want to weld in there and it's relatively resistant to fire and hot sparks!

Anyway if anyone's interested here's the progress so far.

 

[woodpig]

Looks good, what's your plan for the floor?

 

[PAC1]

Just a question before you get too far but have you checked building regs they used to say something about building close to the boundary?

 

[ollied1981]

If you're within a metre of the boundary building regs say the building has to be substantially noncombustible if it's got a floor area more than 15 square metres, but this is about 12 so I'm OK

Plan for the floor so far is just to paint it to keep the dust down. I'm used to working on an uninsulated concrete floor but if it does prove too cold I might put an inch of polystyrene down then some plywood on top.

 

[woodpig]

Plywood on top of some insulation is a lot kinder to your feet than concrete if you can run to it.

 

[Wizard9999]

Ollied

Looks like great progress so far on the 'shop. One comment, when building mine the advice I had was OSB on the inside of the walls, breather membrane on the outside. The logic being the OSB is so full of glue it acts as a vapour barrier, but if any moisture does get into the frame cavity the membrane lets it out through the outside. As you say batten before cladding to allow the breather membrane to do its thing.

Looking forward to seeing more.

Terry.

 

[blackrodd]

An excellent post! good pics and tidy job site. You have obviously done you're homework regarding the build,
looks a professional job!
If you say you are more into metal work, that would be really interesting to see.
Regards Rodders

 

[ollied1981]

@Terry,
I've thought about putting the OSB on the inside as you say, but I wasn't planning to insulate the walls at first which I guess you would need to this way around. Also then the insulation would be directly against the membrane...how does this work out? I guess if you were using solid boards like Kingspan it would be ok but my initial reaction was just to stuff the cavity full of rockwoll because it's so cheap! What kind of insulation did you use?!

So this weekend once it stopped raining I put the roof deck on with a temporary covering of spare DPM:

Oliver

 

[Wizard9999]

@Terry,
I've thought about putting the OSB on the inside as you say, but I wasn't planning to insulate the walls at first which I guess you would need to this way around. Also then the insulation would be directly against the membrane...how does this work out? I guess if you were using solid boards like Kingspan it would be ok but my initial reaction was just to stuff the cavity full of rockwoll because it's so cheap! What kind of insulation did you use?!

So this weekend once it stopped raining I put the roof deck on with a temporary covering of spare DPM:



Oliver

Oliver

Yes, I did do OSB, insulation then membrane on the outside. I used cavity batts for insulation, basically the same stuff as you put in a roof but stiff enough not to slump in the cavity, like this:



Then breather membrane went over that, stapled to the frame:


I then put battens on the outside before cladding in feather edge board:


Seems to have all worked fine. If I had my time again I would probably not stuff the insulation in as much as I did as there was a little bulging in places which closed the gap to the cladding a bit, but hopefully this won't cause problems down the line.

If it is of any interest I did decide to put down 25mm of polystyrene insulation over the concrete floor and then laid 22mm T&G chipboard flooring...


...which I then painted with Leyland floor paint


Very happy with the result, feels kinder on the feet than the concrete did and just feels more comfortable generally. If head height and budget allows I would recommend it, but it is a relatively easy retrofit, well compared to adding insulation in the walls anyway. So if it was a choice between allocating funds to insulate the walls or put a floor over the concrete floor I would go for insulation in the walls with the 'right' construction.

Hope that helps,
Terry.

 

[pike]

Good stuff. That's just paint on floorboards? Great looking effect.

 

[Wizard9999]

Good stuff. That's just paint on floorboards? Great looking effect.

Yes, exactly. Two coats of Leyland floor paint straight onto the floating chipboard floor that was simply glued together. The chipboard flooring sits directly onto 25mm expanded polystyrene, no battens involved.

Terry.

 

[ollied1981]

Terry,
What you made looks a neat job and very similar to mine aside from the brick plinth!

Pretty certain now I'll go with the OSB on the inside. I was thinking pallet banding might be a nice way of keeping all the insulation within the cavity and stop the membrane being pushed out. Was thinking horizontal bands all the way around the building maybe every 250mm in height or so...

 

[MMUK]

Good stuff. That's just paint on floorboards? Great looking effect.

Yes, exactly. Two coats of Leyland floor paint straight onto the floating chipboard floor that was simply glued together. The chipboard flooring sits directly onto 25mm expanded polystyrene, no battens involved.

Terry.

I assume that with no mechanical fixings you glued the T&G joints? Like you would with laminate?

 

[Wizard9999]

Terry,
What you made looks a neat job and very similar to mine aside from the brick plinth!

Pretty certain now I'll go with the OSB on the inside. I was thinking pallet banding might be a nice way of keeping all the insulation within the cavity and stop the membrane being pushed out. Was thinking horizontal bands all the way around the building maybe every 250mm in height or so...

The similarity had not escaped me either. And we haven't even started on an EPDM roof which I have as well, brilliant stuff! I think the banding idea is a good one.

Looking forward to seeing progress.

Terry.

 

[Wizard9999]

Good stuff. That's just paint on floorboards? Great looking effect.

Yes, exactly. Two coats of Leyland floor paint straight onto the floating chipboard floor that was simply glued together. The chipboard flooring sits directly onto 25mm expanded polystyrene, no battens involved.

Terry.

I assume that with no mechanical fixings you glued the T&G joints? Like you would with laminate?

Exactly, no mechanical fixings, just glued together.

Terry.

 

[ollied1981]

So Friday saw the arrival of 11 sheets of OSB3. This was the third supplier after the previous two had delivered OSB2 'by mistake' then claimed not to know what the difference was. I really wonder whether everyone gets OSB2 unless they notice what's printed on the board!

Anyway all the walls have now been boarded out now. I had to make a few more cuts than planned as originally I was going to put the OSB on the outside and had positioned the studs for that, but no matter.

A friend had suggested that it would be a good idea to put a strip of DPC under the floorplate, so I took the opportunity to before bolting the thing down. I raised each side a few mm in turn with a second borrowed trolley jack and slid the DPC under. So now it's bolted down and I don't think there's much chance of it blowing away!

Here's the boarding:

And the fixings:

Next step insulation and breather membrane.

 

[Mcluma]

That looks really good, how much overhang have you given yourself on the roof?

 

[ollied1981]

Hi Chris,
The overhang is 150mm. Planning on some approximately 4x1" around the edge then capped with UPVC fascia board.

 

[Mcluma]

As its raining today,

just have a look at the front how wet your timbers are getting - especially at the bottom??

If you could - can you still increase it to about 300mm? it will leave your foundation, as well as your timber so much dryer

 

[Wizard9999]

Looking really good. I think the two large, but high windows will prove a good design decision, max light without interfering with layout.

Terry.