Loft insulation in Thorney Hill

The laying part of a Thorney Hill loft is not complicated. One layer between the joists, friction fitted so there is nothing open at the sides. A second cross laid over the joists at right angles so the timber is buried and stops conducting heat down into the room.

Around 270mm all in is what a renovated ceiling is expected to reach under Part L in Approved Document L, and the second layer is where most of the gain in the U value sits. Mineral wool roll along a clear run, rockwool batts where an older cut roof puts every bay at a different width, glass wool, sheep wool if you would rather, loose fill in the corners, and PIR rigid board such as Celotex or a multi-foil quilt where the headroom has simply gone. Then the fittings: fire rated covers over recessed lights and downlighters, cable and wiring lifted above the new layer instead of buried in it, lagging on the cold water tank and its pipework, and a board and draught seal on the hatch.

Boarding straight onto the joists. It is a common wish and it undoes the job. Chipboard screwed down in a Thorney Hill loft compresses the wool underneath to a fraction of its depth, so the part of the ceiling you crush is the part over the room you use most. Storage goes back on loft legs, with a raised floor clear of full depth and the boarding kept to the platform you actually need. If the joists will not carry the loading we say so before anything is fixed, and the loft ladder is reset to the new height.

Packing the eaves. The second habit, and the expensive one. Insulation in a Thorney Hill loft is meant to run out over the wall plate and stop, with a vent tray at each rafter keeping an air gap open above it so cross ventilation can carry moisture from one side of the roof to the other. Push it on into the corner to make it look finished and the roof stops drying: the dew point moves into the layer, interstitial condensation forms out of sight, water gathers on the underside of the felt and black mould works down the rafters. Where the eaves are boxed and cannot be reopened, a ridge vent or a run of tile vents does the job from higher up, and a breathable membrane changes the detail rather than the requirement.

Laying over material that is wet. The third. New wool on top of damp wool in a Thorney Hill loft hides the problem and doubles the cost of fixing it later. Anything that has settled and gone patchy but is dry and sound stays and gets levelled out. Anything damp, anything broken down into dust and anything contaminated with droppings is bagged in the loft and taken away, and we find out why it was wet before anything replaces it. Occasionally that means the honest answer is to fix a slipped tile or a fan discharging into the roof first and do the insulation afterwards, and we would rather say that than sell you material twice. Where the roof has already been converted to a room in roof, none of the floor work applies and it becomes a warm roof at rafter level instead, with taped joints, a vapour control layer and the sloping ceiling and dormer cheeks done properly.

Measuring the loft floor takes a minute. The awkward edges are where the time goes. Getting in. An old cottage with a small trapdoor in a back bedroom, a detached house with a proper loft ladder, and a bungalow with a shallow roof you can only crawl through each need a different plan for getting materials in.

What is up there. Old compressed material has to come out, be bagged and taken away, and a loft full of stored boxes has to be emptied and put back. Evenly spaced joists with nothing in the way go quickly; a trussed roof full of bracing is slow.

The eaves. On a low pitched bungalow roof the gap at the eaves is tight, and the insulation must stop short behind a tray so air still moves, or you swap a warm room for a wet roof.

Boarding. If you want to store things up there, raised legs go in so the boards sit above the full depth without squashing it.

The standard. Approved Document L sets what the work is expected to reach.

Check that any other quote states the finished depth and number of layers, keeps the eaves open, and covers the hatch and pipework.

Addresses here sit inside the New Forest National Park, so the planning authority is the National Park Authority rather than the district council, and the National Park property map is where you check any particular address. There is no conservation area over the village and barely anything on it is listed, so for most houses the constraint is not heritage consent. It is the Park's interest in how things look from outside.

For this job that interest reaches almost nothing. Insulation over a ceiling is inside the building, invisible, and needs no application to anybody. The one place it can touch is ventilation. If a roof has soffits that are boxed in and cannot be opened, the neat answer is vents in the slope or along the ridge, and those do show. Permitted development rights are narrower inside the Park than outside it, so that is worth establishing before the work rather than after. In practice we would rather take the air at the eaves anyway, which keeps the roof looking exactly as it does now and saves the conversation altogether.

Thorney Hill is 6.8 miles from Wolverton Road in Boscombe, where our base is. We insulate lofts there and in Bransgore, Burley, Burley Street and Sopley. Planning rarely comes into loft work here, and when building control does apply it is New Forest District Council.

Bournemouth Roofing & Building Ltd is registered in England and Wales, company number 15471719. Its owner, Thomas Hannen, climbs into your loft and prices it himself. A verified customer on Checkatrade gave us 10 out of 10. Neither the visit nor the itemised written quote costs anything. Before you book a visit in Thorney Hill, you can read our customers' Google reviews, word for word, on our reviews page.

Most repairs in Thorney 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.