Workshop base - Does this sound right?

[paulc]

After a break from building a new workshop, due to being afflicted with the longest lasting flu ever recorded, I'm back at it , and as ever full of questions for the forum.

I've laid the footings (9 cement footings with blocks ontop) and want to begin the base. How does this sound:

* Joists of 8 x 2 tanalised timber , with a dpm running between them and the blocks and pinned/stapled to outside of joists all round

*16" centres to fit rockwool insulation (one of main priorities for shop is noise reduction)

*Thin ply sitting on strips of wood at inner sides of joists for rockwool to sit on

*Breathable vapour barrier on top of joists/rockwool overlapping dpm on sides

*12mm wbp ply on top of this as flooring

Then tarp the whole lot over and hope it doesn't get soaked while I'm getting the walls and roof on.

Well hows that sound, any info / feedback much appreciated, Cheers , Paul

 

[speed]

sounds ok apart from the 12mm floor, i would go 3/4. you can get MR chipboard flooring 8'X2' for about 7quid.

 

[Rich]

Hi Paul, your base sounds good to me, if it's any help here's how I went about mine,
size of shed=12'x8'......conblock base made 4" bigger all round.
conblock base was doubled up to make a "raft" this wont go anywhere.
single blocks placed evenly inside the raft and 4x4 timbers laid on these to bring it up to the same height as the outer base.
all bearing surfaces covered with a dpc and then the hd floor set in position and screwed down with 6" screws.
walls and roof erected, 8'x2'x18mm loftboards then laid and screwed across the run of the floor.
then I ran some 4x2 through the t/s at 45 degrees, cut to length and screwed to the block base/ outside walls to act as runoofs for rain etc.
all painted with wayerproof coat, seems okay so far.
Regards, Rich.

 

[jasonB]

Consider chicken wire with 1/2" holes tacked to underside of joists to keep vermin from nesting, this will also support the insulation.

Rigid insulation is another option but a little more expensive

At least 18mm ply, the 22mm flooring ply is good as it comes in 8x2 sheets and has T&G edges like chipboard flooring. Screw it down rather than nail

Cant comment on joists without knowing the span

Jason

 

[Wood Monkey]

Hi Paul

I'd echo the other comments re: the 12mm ply. I clad the walls of my workshop with this and I can see a bit of flex if I lean heavily on it, so on a floor I think it would be a bit light. I'm just putting down 18mm T&G sheets on my floor (pics in a few days) and it was £6.49 per 2400x600 (8.2) sheet from Wickes.

 

[Anonymous]

I've had chicken wire recommended several times. I wouldn't touch it with a bargepole. It's horrible stuff to get rid of when it's rusted and gone dodgy. Also most animals round my place would get through the stuff no problems. The mice in the house get under the doors!

Can't say I've worked out what to use to stop the animals yet though. Maybe leave it breezy enough so they don't like it under there.

I've used 6x2 for floor joists and feel like I've overdone it. Not sure I'd bother with 8x2. I think I'm putting seconds kingspan under the floor with dpm over the top. That will ensure joists get air to them.

Dave

 

[mailee]

My flooring is 19mm T&G floorboards sitting on 6X2" joists and it stands up well. I have a lot of machines in there and a 270kilo table saw in the centre on wheels which I have moved around a bit. :wink:

 

[martlewis]

Fell lucky when building my 8' x 18' shop, was given a stack of 8' steel reinforced concrete fence posts. Laid across b/block foundation, dpm and some 2x2 running along posts and 18mm t&g chipboard flooring sheets running opposite way. With the heaviest maching rolling around on wheels there's not a mm of deflection!

Martin