Garden Room & Loft Conversion Materials: What You Need
Garden rooms and loft conversions are two of the most common projects our customers buy materials for. This guide lists the main materials each one needs, so you can build a rough shopping list before you order. Every project is different, so check your drawings, your structural engineer's details and Building Regulations (or your building control officer) before you buy. We do not give prices or quantities here: use our calculators to work out how much you need.
Garden room: what you need
A typical insulated garden room or garden office is a timber frame on a base, with insulation in the floor, walls and roof and a finish inside. The main material groups are:
Base and floor
- Sub-base and concrete for a slab or pads: cement and aggregates, including MOT Type 1. See our MOT Type 1 guide and aggregates calculator.
- Damp proof membrane under the floor: membranes.
- Floor joists or bearers: timber.
- Floor insulation between or over the joists: PIR insulation boards.
- Floor deck: OSB or other sheet materials.
Walls
- Stud frame: timber.
- Sheathing on the outside of the frame: OSB or sheet materials.
- Breather membrane behind the cladding: breather membranes.
- Insulation between the studs: PIR boards or glass wool.
- Vapour control layer on the warm side: vapour control layers.
- Internal finish: plasterboard or insulated plasterboard.
Roof
- Roof joists and deck: timber and OSB.
- Roof insulation: PIR insulation boards (or Celotex).
- Vapour control layer and ceiling board: vapour control layers and plasterboard.
Fixings and finishing
- Screws and fixings: Evolution fixings.
- Drylining sundries such as tape and jointing: drylining.
Loft conversion and loft insulation: what you need
A loft can be insulated at the ceiling joists (a cold loft, for storage) or at the rafters (a warm loft, needed if you are turning it into a room). The materials differ, so decide which you are doing first. Our where to insulate guide explains the options.
Cold loft (insulating the floor of the loft)
- Loft rolls between and over the ceiling joists: loft insulation and glass wool. Use our loft roll calculator.
- Boarding for storage, raised above the insulation: sheet materials.
- Loft hatch: access panels.
Loft conversion (warm roof at the rafters)
- Insulation between and under the rafters: PIR insulation boards or Celotex. Check the U-value with our U-value calculator.
- Breather membrane if the roof is being re-felted: breather membranes.
- Vapour control layer: vapour control layers, or use insulated plasterboard as the under-rafter layer.
- New floor joists, studwork and dwarf walls: timber or metal studs and track.
- Floor sound insulation between the joists: acoustic mineral wool.
- Floor deck: sheet materials.
- Walls and ceilings: plasterboard and drylining sundries.
- Fixings: Evolution fixings.
Working out quantities
- Insulation calculator for PIR boards and slabs.
- Plasterboard calculator for walls and ceilings.
- Loft roll calculator for cold lofts.
- All calculators.
Delivery
We sell at trade prices to everyone and deliver to addresses in England. Insulation, plasterboard and drylining orders have a £400 ex VAT minimum and free delivery. Timber, aggregates and cement have a £250 ex VAT minimum, with £25 delivery under £500 and free delivery above. Celotex has a £250 ex VAT minimum, with £40 delivery under £550 and free delivery above. See our delivery information for everything else, or call 03330 908479 with your list.