How to insulate a shed on a budget

[smiley65]

its 3/4mm thick

 

[Rorschach]

Yeah you are wasting your time.

 

[smiley65]

back to builders paper and polystyren i think

 

[jonbee56]

Or 4” polystyrene covered with flame resistant Corex stapled to the joists. Used on my workshop ceiling. Safe and warmer

 

[smiley65]

only have enough space for 25mm and that allows a gap of 35mm

 

[johnnyb]

Given the cost of a cheap shed v the cost of insulation I reckon 2/3 layers of bubble wrap would make a real significant difference. Don't use egg boxes.

 

[MikeG.]

I’m no expert (need to wait for MikeG to come along), the question to ask is...where does that water go? It will drain to the bottom of the cavity and rot the sole plate and any other timbers it contacts. You have to prevent water or water vapour getting in and/or provide sufficient air gap to allow moisture to evaporate.

Spot on. Having insulation hard up to the back of the cladding means any water that gets in can't dry off in circulating air, and will be held against the back of the boards by the insulation.

 

[Duncan A]

This may not be relevant, but I read somewhere that polystyrene degrades PVC electrical insulation so they shouldn't be in contact with one another, for example behind the internal plywood cladding.
Duncan

 

[MikeG.]

This may not be relevant, but I read somewhere that polystyrene degrades PVC electrical insulation so they shouldn't be in contact with one another, for example behind the internal plywood cladding.
Duncan

I don't know about polystyrene, but expanding spray foam certainly does, and should ever be sprayed around cables.

 

[smiley65]

hi mike thanks for input,when i install the builders paper on inside of shed does it matter if it is touching the outside wall of shed and then 25mm gap for insulation then ply to cover all,also should i add a couple of air vents?

 

[mikej460]

I used foil quilt insulation to dry line rooms in our old house. It works really well and is easy to put up - just follow the videos on the excellent ybs insulation website

Aldi recently had some on offer.

The only downside I've noticed is a degradation in mobile phone signal but DAB radio works ok.

I wouldn't put polystyrene in a workshop on safety grounds but whatever insulation you use you may need a vapour barrier stapled down first then battens to give you the 25mm gap others have mentioned (also shown on the videos).