When it comes to insulating a flat roof you can go for two options.
Garage conversion flat roof insulation.
The first step will be.
Typically 150mm deep flat roof joists will receive 100mm of pur insulation between the joists and 50mm beneath them floor insulation is always absent in a garage and including some in the conversion should be part of the project whenever it s possible.
However if you have a cathedral style garage roof you will need a scaffolding to get into the upper areas of the roof.
A warm roof or a cold roof.
Jeremy broun shows how he insulates the walls and roof using dot and daub polystyrene slabs and plasterboard and offers a handy painting tip too for concrete.
You should use some foil tape to make sure that the insulation is stable on the roof edges.
You can buy insulation kits for standard metal garage doors or you can cut pieces of rigid foam insulation to fit each door panel section.
The tape will also make sure that there is an air pocket available in the insulation.
However if it s in a fairly poor state it may be more prudent to replace the roof during the garage conversion process.
That s right even your floor needs insulating.
Flat roofs are harder to insulate through diy and it s recommended that your find a professional to help with installation.
Make sure that all of the pieces are the same size so that they fit into the trusses.
A warm roof in a flat roof situation normal when re roofing is required consists of loft insulation between and to the top edge of the firings long wedges that sit on top of the joists to form the water run off or very slight pitch then cellotex of around 80mm thickness followed by 18mm plywood or stirling cheaper board followed by the final water proof covering felt fiberglass.
When a previously insulated room above the garage exists before the conversion then roof insulation will not be an issue and you will not have to add extra insulation to the garage ceiling.
It is possible to insulate your existing garage flat roof.
The space created above the garage would also have to be fully insulated in a similar fashion to the garage.
A cold roof is when your insulation material is fixed between the roof joists.
In either case you will need to follow the general steps below to insulate your garage roof.
If you have a flat garage roof and an attic above you can install the garage insulation from below using a standard ladder.
To install the insulation overhead you need to staple the pieces to the roof trusses.