Insulating a roof


DRAUGHTPROOFING BETWEEN RAFTERS FITTING BLANKET INSULATION FITTING SHEETS OF EXPANDED POLYSTYRENE

If a loft is to be used for storing valuables that could be affected by extremes of temperature, it is better to insulate the roof rather than the loft floor.

DRAUGHTPROOFING BETWEEN RAFTERS

If there is no felt on the underside of the roof, fix building paper between the rafters before putting up any insulation material. This will help to keep out draughts and in-driven rain and snow.
Standard building paper consists of two sheets of tough paper held together by a central layer of bituminised fibre netting. The paper is available in rolls of 3Oft x 3ft (10 m x 1m) from most buflders' merchants.

Things you will need
Tools Steel tape measure, scissors, pin hammer, waterproof adhesive tape.
Materials Rolls of building paper, brass drawing pins.

1. Measure the gap between two rafters and cut the building paper into strips that are slightly wider than the gap.
DRAUGHTPROOFING BETWEEN RAFTERS
2. Start at the top of the roof and pin the paper to the rafters on each side at intervals of about 4in (100mm).
3. Take the paper right down to the eaves. Push out the end of each strip of paper so that any in-blown rain or snow cannot drip onto the loft floor.
DRAUGHTPROOFING BETWEEN RAFTERS
4. To join the paper, make an overlap of at least 4in (100mm) and tape over the join with adhesive tape.

FITTING BLANKET INSULATION

If you can find rolls of glass fibre or mineral fibre with backing paper, you will be able to use the paper to fix the material in place. Arrange it so that the paper faces into the loft and use drawing pins to secure the paper at 6in (150mm) intervals. If the blanket does not have backing paper, hold it in place with string lengths wound round tacks.
Things you will need
Tools Heavy-duty scissors or an old serrated knife (such as an old bread knife), hammer, steel tape measure, face mask, Possibly cotton gloves if your skin is sensitive to fibres.
Materials Rolls of glass-fibre or mineral-fibre blanket, tacks, ball of string.

1. Starting at the top, hammer a tack into the side of a rafter. Do not hammer it right in, let it protrude by at least 1/4in (6mm).
2. On the adjacent rafter, hammer in another tack about 6in (150mm) farther down. Continue in this way, alternating between sides and moving gradually down the rafter until there are tacks sticking out from both sides from top to bottom.
3. Measure the gap between the rafters and cut blanket to fit.
4. Tie the end of the string to the tack at the top of the rafter.
5. Place the insulation material between the rafters. If possible, get someone else to help you.
FITTING BLANKET INSULATION
6. Starting at the top, wind string between the tacks so that it zigzags down to hold the blanket in place.
7. Continue this procedure. If you have to join pieces of blanket, butt them together.

FITTING SHEETS OF EXPANDED POLYSTYRENE

Expanded polystyrene is more expensive than fibre blanket but easier to fit.

FITTING SHEETS OF EXPANDED POLYSTYRENE
1. Cut a sheet of expanded polystyrene to the exact width between the rafters, and push it in so that it fits tightly.
2. Hammer nails or tacks into the rafters below the sheets so that they protrude and prevent the sheets from dropping down.
3. Butt-join the polystyrene sheets whenever you need to use a new piece to make a joint.