Few questions on a shed/workshop build

[Jameshow]

I welcome advice on my family members garden shed design list:
Small 8' x 6' by about head height with a felted pitched roof with similar wood to the neighbours !!! (4" wide or so horizontal T&G with a brown stain look) to keep some gardening tools.

I welcome any/ all advice on T&G, will it shrink and expand leaving gaps and buckle with excess swelling.

I'd start your own thread in the workshop section.

I'd use 3/4 plywood floor and roof.

4x2 floor and roof joists 3x2 studs on 24" centers.

If apex then a 6x2 ridge beam.

Make sure the timber is aclimatised to the outside if its either dripping wet or bone dry!

Cheers James

 

[mikej460]

I'd start your own thread in the workshop section.

I'd use 3/4 plywood floor and roof.

4x2 floor and roof joists 3x2 studs on 24" centers.

If apex then a 6x2 ridge beam.

Make sure the timber is aclimatised to the outside if its either dripping wet or bone dry!

Cheers James

Hi James
what sort of ply would you recommend for internal walls and roof sheathing?

cheers

Mike

 

[Woody2Shoes]

Hi James
what sort of ply would you recommend for internal walls and roof sheathing?

cheers

Mike

OSB3 rather than ply

 

[Spectric]

Yes 4 by 2 is the way to go but there is no such beast anymore since we went metric. You need to buy all your "4 by 2" from one supplier because the size does vary, some suppliers really do stretch the term 4 by 2 . I found this out on a stud wall years ago, all level one side but two were out by nearly 6mm on the other and these two were from a different sawmill. You will also find CLS nicer to work with and I like to use C24 for outside. If you see the brand Holmen on the timber I find that tends to be nice and straight more than not. As for the DPM, yes under the bricks but I would also sit the timber on something so it is not in direct contact.

 

[Jameshow]

4 X2 is usually 3 3/4 X 2 3/4

Cls is 3 1/2 X 1 1/2

You can use OSB but I don't tend too as I prefer a more board.

9 mmwill be fine either way.

cheers James

 

[The Bear]

Remember wood isn’t only treated to prevent rot. Treated wood wouldn’t only help on your sole plates. Treated wood also inhibits mould fungus and insect attack so I’d use it on all your stud work and rafters given the relative price.
I’d get myself down to my local builders merchants and buy regularised treated c24 or c16. 4x2 vs something else largely depends on the size of the building, spans and thickness of insulation required. Sheathing can be any board you like. Osb3 is good. Shuttering ply or better also works just don’t let it stay wet for too long before your roof covering or cladding.
And def get the wood 2 courses above ground level with a dpm on top of the bricks

mark

 

[Sheptonphil]

Could you please explain why this way is so important for the wall layers as I am planning on internally finishing and insulating it. What way did you do it and what problems did you run into. Thanks

Because the way you specced the wall construction, the OSB on the outside acts as a non permeable membrane, meaning any moisture in the wall is trapped. Put it on the inside and that will act as your vapour barrier Due to the high glue content.

my build was, from the inside, fireline plasterboard (cos I had to) OSB, rockwool insulation, breathable membrane, counter battens, cladding.

walls were constructed of 4x2 c24 timber. built In 3m and 4m sections all bolted together. See the thread in the workshop build section. New workshop for 2020

 

[Rob Cheetham]

Because the way you specced the wall construction, the OSB on the outside acts as a non permeable membrane, meaning any moisture in the wall is trapped. Put it on the inside and that will act as your vapour barrier Due to the high glue content.

my build was, from the inside, fireline plasterboard (cos I had to) OSB, rockwool insulation, breathable membrane, counter battens, cladding.

walls were constructed of 4x2 c24 timber. built In 3m and 4m sections all bolted together. See the thread in the workshop build section. New workshop for 2020

Thanks for the reply. I understand what you mean now. I think I have just been thrown off a little as most videos I have watched on youtube show:

cladding - membrane - osb/ply - stud - insulation - finish.

Think I need to watch more vids on actaul insulated garden buildings instead of just sheds lol.

But I totally undertstand about the air gap now and counter battens so will go the way off mikes build like you did.

Also after you had done your frame did you put up the breather membrane, counter battens and then cladding first. Then add the osb and then plasterboard or did you do it the opposite. Im guessing you went outside first as to keep stuff dry if it rained lol

First off I really need to get this concrete slab down first haha. Gonna be a busy next few months. Damm work haha

T

 

[TRITON]

2.) I was thinking using 2x4 all around as I will be insulating the walls inside eventually aswell, so will need the depth for the insualtion. Is this overkill or will 3x2 be sufficiant?

Think of the weight youre putting on it, the roof, the internal timbers, the stuff youre going to hang on the walls. Last thing you want to do is for a wall to buckle. I'd even consider putting the uprights closer together, really beef it up. You'll only get the one chance to do this.

 

[TheTiddles]

Thanks for the reply. I understand what you mean now. I think I have just been thrown off a little as most videos I have watched on youtube show:

cladding - membrane - osb/ply - stud - insulation - finish.

Think I need to watch more vids on actaul insulated garden buildings instead of just sheds lol.

But I totally undertstand about the air gap now and counter battens so will go the way off mikes build like you did.

Also after you had done your frame did you put up the breather membrane, counter battens and then cladding first. Then add the osb and then plasterboard or did you do it the opposite. Im guessing you went outside first as to keep stuff dry if it rained lol

First off I really need to get this concrete slab down first haha. Gonna be a busy next few months. Damm work haha

T

That’s the trap of YouTube etc.... just because lots of people are doing it, doesn’t mean it’s right!

It’s a bit like split washers for vibration resistance on bolted connections, they’re an “industry standard”, everyone does it... but they don’t actually work

Aidan

 

[Fitzroy]

Sheptonphil answered it spot on. Regards my problem, I watched too much youtube and I've ended up with studwork, OSB, membrane, counter battens, cladding. I'd always planned to insulate in the future and I'm now at that future. So I'm left with the problem of what to do. I'm either going to have to risk it and leave it as is, or try to cut some ventilation channels in the OSB from the inside.

Fitz.

 

[Woody2Shoes]

There's absolutely no point specifying C24 timber (it gives them an excuse/reason to charge you more for it) ask for C16 and you'll get that or C24 - it shouldn't matter one jot as far as your purposes are concerned - what matters is that it has been pressure treated (and is graded for structural use).

 

[Sheptonphil]

But I totally undertstand about the air gap now and counter battens so will go the way off mikes build like you did.

Also after you had done your frame did you put up the breather membrane, counter battens and then cladding first. Then add the osb and then plasterboard or did you do it the opposite. Im guessing you went outside first as to keep stuff dry if it rained lol

First off I really need to get this concrete slab down first haha. Gonna be a busy next few months. Damm work haha

T

After framing, I did on one long side put the membrane and counter battens on before erecting that side, as I had no further access to that side externally until I removed the fence for replacement and did the cladding at the same time.
My work sequence was erect frame, membrane and counter battens, insulate, OSB. At that point it was waterproof from the outside, and OSB is fine in wet conditions for several months. Once roof was on, I could put the plasterboard inside (for fire resistance).


a local builder has has OSB around his site for eighteen months through two wet winters, and it is still in good condition.

There's absolutely no point specifying C24 timber (it gives them an excuse/reason to charge you more for it) ask for C16 and you'll get that or C24 - it shouldn't matter one jot as far as your purposes are concerned - what matters is that it has been pressure treated (and is graded for structural use).

I did spec c16, and all of it arrived as c24, real bonus.

 

[The Bear]

That was my point w2s, maybe not made that clear. My local merchants only stocks c24 so if you go there that’s what you’re going to get.
Mark

 

[Rob Cheetham]

That’s the trap of YouTube etc.... just because lots of people are doing it, doesn’t mean it’s right!

Ill remember this for the future lol. Bit offputting if thats the case that so much on youtube shows it like that and in the end its not the correct way. Think ill always check on here from now on before I commit to anything. Thanks

Sheptonphil answered it spot on. Regards my problem, I watched too much youtube and I've ended up with studwork, OSB, membrane, counter battens, cladding. I'd always planned to insulate in the future and I'm now at that future. So I'm left with the problem of what to do. I'm either going to have to risk it and leave it as is, or try to cut some ventilation channels in the OSB from the inside.

Fitz.

Mayby it would be possible to remove the cladding and membrane to get to the osb then remove and put on inside of stud after insulation. Even if the membrane gets ruined may not cost much to replace that. Depends if you attached with nails or screws I suppose though. Screws would obviously be easiest to remove. Though im just guessing here. Might not work and like you say vents in the osb mite be better.

Did you at all by any chance come across any youtube videos where they actually do it Mikes way?

After framing, I did on one long side put the membrane and counter battens on before erecting that side, as I had no further access to that side externally until I removed the fence for replacement and did the cladding at the same time.
My work sequence was erect frame, membrane and counter battens, insulate, OSB. At that point it was waterproof from the outside, and OSB is fine in wet conditions for several months. Once roof was on, I could put the plasterboard inside (for fire resistance).


a local builder has has OSB around his site for eighteen months through two wet winters, and it is still in good condition.


I did spec c16, and all of it arrived as c24, real bonus.

Thats really good to know that OSB lasts a long time in wet weather. Im assuming becasue of the glue content. Thats one of my main concerns to be honest everything getting wet in the building process. Im a compotent diyer but not a pro and like to take my time. Though the 1200 dpm im looking at getting from screwfix, I should have plenty left over to use as a tarpaulin over structure if it rains. Which being in the UK is highly likely at some point

Sorry if you have already mentioned but did you use complete treated c16 for the frame or just for the soleplate and roof. What about the counter battens. Were they treated?

Thanks