Loft insulation in Beacon Hill

In a cold loft, the insulation sits on the ceiling. The loft floor is then one of the main routes for heat loss, which is why depth over your head is usually the first thing worth checking.

What is often in an older loft is one layer of mineral wool, glass wool or rockwool, pushed between the joists and compressed thinner than the packet ever claimed. A second layer of roll goes over the top, cross laid across the joists, so the timber stops being a cold bridge. Two layers, around 270mm finished, is what gets a ceiling to the U-value Approved Document L asks of a renovated thermal element under Part L.

What is already there decides whether it stays. Wool that is only compressed and patchy gets straightened and covered. Loose fill that has drifted, anything contaminated by droppings and anything sitting wet comes out, bagged at the hatch, and leaves with us. Batts go in where joist spacing is awkward, sheep wool where somebody wants it. Access is the first thing we look at, since it is still work at height even indoors.

The eaves are the part that gets ruined. Insulation in a Beacon Hill loft runs to the wall plate and stops. Beyond it is the air gap the roof breathes through, and pushing new depth into the eaves swaps a warm bedroom for a wet roof. A vent tray at each rafter holds that path open so the material still reaches the edge rather than stopping short and going missing where the cold gets in. Where the soffits are boxed solid and the underlay is old felt rather than a breathable membrane, the cross ventilation is not working and a ridge vent goes on first. Otherwise you get condensation on the felt and mould on the timbers.

A room in the roof is a different job. Where your house has a room up there, the ceiling you stand on is not the surface losing heat. Sloping ceilings, dormer cheeks and the flat top all want rigid board, PIR such as Celotex cut tight between the rafters with a clear gap above it, a second layer under, then a vapour control layer taped so warm air cannot get into the build up and find its dew point inside the timber. That is a warm roof. In a room in roof with almost no depth to spare a multi-foil quilt earns its place.

Then everything else up there. Downlighters and any other recessed light take fire rated covers, wiring is clipped above the new layer rather than buried in it, and the cold water tank and its pipework get lagging now they sit out in the cold. Storage is planned: loft legs and a raised floor over the insulation, a platform boarded where you need one, the hatch insulated and draught sealed, the loft ladder checked against the new floor.

A loft is quoted on the job, not the floor area. Rolling out the open middle goes fast; the edges, the hatch and anything stored up there are where the hours go.

The way in. A hatch on a landing where a ladder stands square is easy. A hatch above the stairwell, a chalet whose rooms in the roof leave only crawl spaces behind the knee walls, or a tight hatch in a bungalow hall ceiling all slow things down.

What is already there. A thin, flattened layer can usually stay, with new rolls laid across it at right angles. Anything damp or dirty is bagged and taken out first, and boxes and boarding that have to come up and go back take time too.

The structure. Joists at close centres with open bays between them go quickly. A trussed roof full of diagonal bracing means every roll is cut to fit round the webs.

Airflow and the edges. The insulation stops short of the eaves so air can get under the tiles; block that and the felt and timbers get wet. Pushing full depth into the corners and over the wall plate, sealing round the hatch and lagging the tank are most of the labour. Approved Document L sets the target.

Storage. If you still want to use the loft, a raised deck on legs keeps the insulation at full depth underneath.

Before you pick a quote, ask what depth is going in, whether the old material is coming out, and whether the eaves, the tank and the hatch are all covered.

From our base on Wolverton Road, Boscombe, Beacon Hill is 9.8 miles, and we insulate lofts here and in Sturminster Marshall, Lytchett Minster, Upton and Corfe Mullen. Dorset Council is the building control authority. The firm is Bournemouth Roofing & Building Ltd, registered in England and Wales, company number 15471719. Before you book a visit in Beacon Hill, you can read our customers' Google reviews, word for word, on our reviews page.

Its owner, Thomas Hannen, climbs into your loft himself, measures what is there and puts the price together. A verified customer has marked us 10 out of 10 on Checkatrade. The visit, and the written quote itemising everything, are both free of charge.

Most repairs in Beacon Hill need no application at all. What decides whether a change to the outside of your house does is who the council is, whether a conservation area or a listing applies, and whether the place sits in a protected landscape.