Insulating a woodern workshop

[pjo123]

Hi all, I've read a lot of the older posts on here but am as confused as ever

I built this shed myself (pics at bottom, don't laugh, my first attempt at building one) and want to insulate it as cheaply as possible (wifes going mad as it is, over the amount I've spent).

The main thing that concerns me is the gap the older posts recommend having.

I have two affordable means of insulating. One is by using a roll of loft insulation, and I already have a roll that will do 14 sqr yrds at 100mm thick and I'm presuming I could split it in half so I have around 50mm thick.

The other way is to use 50mm polystyrene sheets.

Trouble is I used 50mm for my timbers so if I use either of those methods, I leave no air gap. But as the walls are all shiplap, wouldn't enough air be able to get through the gaps anyway?

If I go the loft insulation route, should I line the walls with polythene first on the off chance that water did get in somewhere?

As far as the roof goes, I'll stick some batons across to allow a gap then use polystyrene sheets.















Many thanks for your help

Phil

 

[JohnD]

you will find it much easier to put fibreglass into those uneven gaps. You could put breather paper in first (rain spray will penetrate shiplap a bit).

I don't suppose you will be generating much moisture inside the shed so condensation shouldn't be a prob.

You will need to line the walls so you don't keep brushing against the insulation. thin ply would do. WBP is moisture resistant. I would have thought about 9mm or nearest size would do. Pencil in the positions of the studs so you can screw through the ply to hang things. it will also make the shed more rigid.

Hope you have raised it off the ground a bit as damp will rot it if not. You can apply wood preserver to the lowest 150mm - 30mm if you like (I use Cuprinol green)

Don't forget to insulate the floor or it will be very cold on your feet. You could use the foam slabs here with flooring ply on top (it is quite strong like that and needs no battens)

 

[Deluks]

Kind of a backwards way of doing it, but, counterbatten the walls with horizontal 2x2 (spaced apart the same width as the insulation), fit the foam sheets between these and ply or plasterboard over. You will then have a healthy 50mm gap directly behind the outer cladding, which is essential as it should breathe from behind.

Has that skylight started leaking yet

 

[pjo123]

Thanks all.

Yep it's raised off of the ground.

So far no leaks in skylight, but shed not even finished yet

 

[pjo123]

I've decided to put 25mm batterns over the existing timbers.

The gaps aren't as uneven as the photos imply. Most gaps are identical, except for either side of where I put the double timbers to attach the floor joist bit to.

Then I will use 50mm polystyrene sheets giving me a 25mm gap between polystyrene and shiplap.

I've read thousands of posts on the net about using a vapour barrier and am more confused than before I started

If I've got polystyrene sheets, do I need a vapour barrier? If do, I presume I have shiplap > 25mm Gap> 50mm Polystyrene > Vapour barrier > inside shed wall?

Can I use normal polythene sheeting for this? If so, won't it keep moisture trapped inside the shed?

As confused as ever

Phil

 

[Deluks]

I've decided to put 25mm batterns over the existing timbers.

The gaps aren't as uneven as the photos imply. Most gaps are identical, except for either side of where I put the double timbers to attach the floor joist bit to.

Then I will use 50mm polystyrene sheets giving me a 25mm gap between polystyrene and shiplap.

I've read thousands of posts on the net about using a vapour barrier and am more confused than before I started

If I've got polystyrene sheets, do I need a vapour barrier? If do, I presume I have shiplap > 25mm Gap> 50mm Polystyrene > Vapour barrier > inside shed wall?

Can I use normal polythene sheeting for this? If so, won't it keep moisture trapped inside the shed?

As confused as ever

Phil

How often will you be using the shed? Build up of moisture inside depends on how often you will be in there, breathing, sweating etc. Or storing anything damp (muddy wellies?, gardening tools?)

In any case you should put a few air vents in the walls, or just under the eaves as that skylight will heat the room causing condensation. Any plastic sheet can be used as vapour barrier, you probably won't need it though t.b.h.

 

[pjo123]

Thanks

Will hopefully be using it for a few hours most days (wife permitting) and will have both my wood turning and my metal working lathes in there.