Insulating a workshop?

**purplemoon**

What is the best/cheapest way to insulate a shed/workshop? I'm assuming the floor and roof would be the most important (the walls are 38mm so much thicker than a normal shiplap shed) and does it make a lot of difference to internal temperatures if it's done?

tawnyowls

Dunno if this is the best/cheapest, but we've insulated one half of our garage by putting up sheets of expanded polystyrene (Aeroboard?), fixed directly to the breeze blocks with No More Nails, and then fitting a false roof of plywood with more sheets of poly on top of that. Yes, it has made a lot of difference - you can really feel the temp difference when you open the door into the other garage.

**purplemoon**

We hadn't thought about polystyrene so will have to look into that, thanks. When you did the roof do you mean you sandwiched the polystyrene between the existing roof and ply sheets, or stuck it on after?

Can anyone tell me if it's worth insulating under the floor before we lay it (and what to use and how please) or would we be just as well to use a floor covering, such as cushioned vinyl, on the inside?

tawnyowls

We installed a ply false ceiling on the rafters and then put the polystyrene on top of that. We could have filled the space with roof insulation, but we wanted the storage.

Yes, if you haven't got a floor down yet, it would be worth insulating below it - a lot of heat goes out through a floor. We had a concrete base in our garage, so couldn't do a lot, and there was going to be a lot of water around, so we put down lots of very cheap doormats (rubber backing with waterproof nylon fibre on top) to at least reduce the heat lost through the floor. For ease of cleaning and extra insulation, cushioned vinyl probably would be useful in your situation.

woodbutcher_2

Jablite is the stuff you want.Comes in different sizes and thicknesses.I would recommend putting it in a new floor.What type of floor are you having?Concrete,timber?

**purplemoon**

It's a timber tongue & groove floor over a solid base so there's room to insulate under it between the bearers. What's the best way to attach this stuff to the underside of the floor?

ETA: what thickness would you recommend for the floor, and would this be ok to use for the roof too? It's an apex roof, I think that's what you call them, an upside down V shape, not flat

woodbutcher_2

You don't need to attach it to anything.Just cut it and lay it between the timbers.I would recommend 50mm thickness for a floor but like all insulation,the thicker the better.This would also be ok for the roof and yes it is an apex roof.