Re: Insulating a shed

[Christian McArdle]

1) Will a two inch layer of old loft insulation plus a layer of

>chipboard actually make much of a difference to conditions inside the >shed, and

Yes. It will. Almost any thickness of insulation makes a big difference. There is a law of diminishing returns which means that the first few centimetres make all the difference.

2) Would a layer of some kind of other material be required to stop > the insulation getting damp?

Yes. I'd put sheet plastic on the outside of the insulation to prevent penetrating damp and line the inside with vapour check plasterboard (i.e. foil stuff with taped joins). Otherwise, just use plastic sheet and chipboard on the inside. Also, consider using expanded polystyrene sheet instead of Celotex. It isn't as good at insulating, but is much cheaper. Obviously, if there is particular fire risk, you may need to take this into consideration.

Christian.

[Arg]

Yep, it makes a huge difference. I would go with both the insulation, and damp-proofing.

Normally, you would but a water barrier on the outside surface, which repels rain but lets moisture escpae from the walls.

On the inner wall, just before you put up the chipboard put up a moisture barrier which stops water getting through from the inside of the shed into the walls.

Bascially, when the temperature changes over a day causes moisture to condense "somewhere" in the walls. You need a moisture barrier to stop it coming into the shed (any impervious plastic will do). The moisture must have a method to escape however - so either don't put anything on the outside wall, or if you do - make sure it's only water repellent, and lets moisture through.

Straw is well recommended as a insulator also - better insulation properties than most fibres - but be careful if you run your electrics through it.

A

[Andy Dingley]

I'd use some solid batts. Hanging rockwool on a wall is a PITA. It also gets pretty fetid if there's any water ingress.

One on the outside, one on the inside too if you're going to be in there.

Outside keeps the rain out (which might also be either unnecessary, or inadequate, depending on your shed). Inside keeps humidity from warm, damp humans condensing in the insulation layer.

[Trev]

What I've done on my shed is to use thick building paper as a lining layer - this is like a thick card roll circa one metre wide, that has either a tar layer on the back or some form of plasticised backing that makes a moisture proof membrane. It can be stapled up quite easily with a staple gun, and trimmed to the uprights - works well for me, and my dad did the same about 20 years ago

Regards,

Trev

[Andy Hall]

ROTFL! Another classic !

.andy

To email, substitute .nospam with .gl

[Terry]

PS. Using recycled wood; various used 'two by fours' (several were 14 feet long) others joined with those pressed in joining plates, plus plywood, all from an old building. Gosh there's a lot of rusty old nails in that stuff! Deliberately using an 'old' saw blade to cut it cos one sometimes hits the odd staple. But wood was free for labour of taking it! So far haven't bought a single item for this particular project! Our half metre satellite TV dish presently feeds one receiver and is presently mounted, about six feet off the ground, on a bracket bolted vertically to on one of the posts of the storage shed. The coax cable from dish to receiver is about 100 feet. The new shed is made so that the bracket can be transferred to mount almost horizontally on it's slightly sloping roof at about same height. Afterwards we will realign the dish. When we originally installed dish we had more trouble getting the correct elevation (only about 22.5 degrees here) as compared to getting the right bearing! BTW we haven't had much deterioration of the satellite signal which is normally displayed as being around 83%; except when some snow accumulated on the dish/receiver and also once IIRC during extremely heavy rain. When we reinstall we intend to use our spare one metre dish and its dual-LNB which will also have capability for two receivers. So the capture area of the dish will be approx. four times that of the smaller dish thus, hopefully, raising the signal level by several db.

[IMM]

I would hate to live in house you would build. "interintestinal condensation", obviously not in your How Things Work book.

[IMM]

LOL!!

[Bob]

I costed Celotex at nearly £300. Since the shed was only £450, and I'm not going to be using it *that* often as a workshop, I'm looking for a cheaper alterntive.

Why is the old insulation not worth it? It's coming out of the house anyway, so it either goes in the shed or to the tip. Would old insulation not be effective?

I definitely plan to plug the gaps - I might need something that can fill bigger holes than a silicon gun :-)

Bob

[IMM]

It flattens and looses its qualities. Try the foam stuff in Wickes.

[Christian McArdle]

The problem is that it is really designed for lofts, where the required thickness for a given u-value isn't much of a problem. In a small shed, you want something that has a lot of insulation in a thin space and that won't compress down, leaving a gap at the top after time. It is also more likely to suffer damp in a shed, where there is no tiles or slate and less room for ventilation on the cold side. Wool type insulation is much worse when wet than solid board.

So in all, the old insulation will be far better than nothing, but solid insulation would be much better still.

Christian.