Insulating a large shed/workshop to use year round

SouthernGuy

Good Morning all,

I'm after a bit of advice please.
In the garden I've got a 20x12ft wooden shed that I want to insulate well to allow year round use but as cheaply as possible. it's use will be a hobby room.

The shed is constructed of 3x2 framing with 23mm loglap cladding to the walls and 13mm t&g roof and floor.

It will be heated/cooled by an air conditioner/heat pump (research suggests this is most economical method and will dehumidify the air etc.

I've been looking at various insulation options such as.

1. Stapling a tyvek Dupont breathable membrane to the inside of the cladding (between framework), placing 25mm or 50mm celotex or equivalent between the framework and then putting ply over the top.

My question regarding this method is:
Is there a cheaper alternative to both tyvek and celotex?

2. Stapling double sided foil bubble wrap to the cladding (between framework), pushing rockwool (loft insulation) in between frame and over boarding with ply.

My questions with this method are:
Will the foil be ok straight against the cladding like the membrane and will it do a similar job to the tyvek?
Is it ok to use loft insulation, I'm worried about vermin liking it for bedding or if it does get wet what damage could be caused.

I also need to think about the roof and floor.

Does anyone have any other suggestions please? I didn't realise the insulation would be so expensive.
I'm keen to get cracking on it as soon as possible.

Many thanks
SouthernGuy

iharding

Search for Seconds and Co. They sell slightly damaged Celotex\Kingspan sheets by the pallet at a discount. They sell through ebay, so if you are patient you can sometimes get an even better deal if no one else bids.

I have previously used Rockwool to insulate an outdoor building, and yes, there were a lot of abandoned mouse nests when we removed it.

Chrishazle

I used foil covered Klingspan for my workshop - the 40mm was the exact depth needed, it cuts to size quite easily with a sharp knife. I then clad the walls and ceiling with 3/4" (18mm) ply, so I can attach shelves etc wherever I want. Works well!

stator

There are plenty of brands apart from Celotex available, the common name is PIR board. If you have a small space then PIR board is the best you can do.
I've got cheap PIR board off gumtree in the past, people sell sheets they ordered but didn't use, also some large offcuts sometimes.

dc197

I'm not familiar with the materials you mention.
I bought a house which came with an insulated shed. When I knocked the shed down, I could see that it had been insulated in the following way: the inside surface covered in PVC sheet, then that covered in fibreglass loft-style insulation, then that covered with a think inner skin of wood.
The trouble was, even though the walls were well insulated, the glass of the windows and the cracks around the door were the weakest (coldest) point.
So watch out of those parts too.

cyclonebri1

Go with 50mm polystyrene, most cost effective practical option.

Plus work harder in your shed, it becomes self heating, :D:D:D:D;)