Loft insulation in Sopley

Getting about. Trussed rafters are braced diagonally end to end and the webs come down close to the ceiling, so there is no walking about and no dragging anything across. Crawl boards go down first, material goes in cut and folded, and the far corners are reached along the line of the trusses rather than across them. That is why a straightforward loft in one of these houses still takes a morning: the constraint is the timber, not the area.

The layer that is already there. Almost every loft on these roads has something in it and almost none of it is enough. It has settled, it is compressed wherever weight has been on it, patchy across the middle and missing at the ends, with a gap round every cable. Dry and sound, it stays and we work over it. Damp, black underneath, or contaminated with droppings, it is bagged where it lies and leaves with us.

Depth, and the layer that runs crossways. One layer sitting flush between the joists leaves every timber conducting straight through the ceiling. The second layer is laid across them at right angles so the joists disappear underneath it, and that is the part that does most of the work on the U value. Around 270mm finished is what Approved Document L expects of a renovated ceiling under Part L. Mineral wool roll where there is a clear run, rockwool batts where the bracing chops the bays up, loose fill blown into the corners a roll will never reach, glass wool, sheep wool, whatever suits the loft.

The perimeter, which is where these roofs go wrong. The original layer in a lot of these lofts was pushed hard into the eaves, and that is the one place it does harm. The insulation should 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 carries damp air from one side of the roof to the other. Block it and the vapour that ought to leave condenses under cold felt instead, the dew point moves into the layer, interstitial condensation builds up unseen and black mould spreads over the rafters. Where the eaves are boxed and cannot be opened, a ridge vent or vent tiles take the job on, and a breathable membrane changes the detail rather than the need.

Lights, tank, boards and the slope. Recessed lights and downlighters get proper covers, wiring is lifted clear so nothing runs hot under the wool, and the cold water tank and its pipework get lagging the moment they find themselves in genuinely cold air. Storage goes back on loft legs as a raised floor so the boarding sits above full depth, with the loft ladder checked against the new platform and the hatch insulated and draught sealed. Where a roof has already been converted, a room in roof needs a warm roof instead: rigid board between the rafters, a taped vapour control layer under them, and multi-foil in the sloping ceiling and the dormer cheeks where nothing thicker will go.

No rate per square metre, because the floor area is the easy part and the awkward edges are where the time goes.

Getting to it. A terraced house with a small hatch on a narrow landing, a bungalow you can move about in, and a cottage with a trapdoor over the stairs are three different mornings, and the climb up is work at height in its own right. A hatch on a landing you can stand a ladder under is one job. A hatch over a stairwell, a crawl space you can only move through on your knees, or a loft full of boarding that has to come up and go back, is time before any material is laid.

What is up there now, and what it is sitting on. Old material that has to come out, be bagged and taken away is a cost before anything new goes down, and so is a loft full of boxes that has to be emptied and put back. Joists at 400 centres with a flat run across them is a different afternoon from a trussed roof full of bracing.

Ventilation, and the edges nobody reaches. Insulation stops at the wall plate and the eaves have to stay clear, or you trade a warm bedroom for a wet roof. Getting depth right into the corners and around the hatch, boxing over downlighters and lagging anything that now sits in the cold, is most of the labour. Approved Document L sets what the work is expected to reach.

Comparing quotes? Ask what depth is actually being laid and in how many layers, whether the old material is coming out or being covered over, whether the eaves are being kept clear, what happens to anything you store up there, and whether the hatch and the pipework are included. Two quotes for the same job are usually two different jobs.

Most of the housing here went up between the war and the early eighties, a good deal of it in the seventies, and a lot of it in terraced rows. Those roofs were built to one drawing, by the same gang, within a season or two of one another, and the same thin quilt was rolled out over every ceiling on the same afternoon.

The useful part is that they wear out in step. If your original layer is flattened to a fraction of its depth and rammed into the eaves, your neighbour's almost certainly is too, and so is the one at the end of the row. That is worth a word over the fence before anybody books anything, because a run of houses done together is quicker per house than the same houses done separately across three different years. It also means that once we have been up in one of them we can tell you fairly precisely what is waiting in yours before the ladder goes up.

We cover Sopley, Bransgore, Winkton, Burton, Christchurch and the Avon valley villages, and the BH23 addresses around them, with New Forest District Council for the planning and the building control. You are dealing with Bournemouth Roofing & Building, the trading name of Bournemouth Roofing & Building Ltd, registered in England and Wales, company number 15471719, which you can look up in a minute. Thomas Hannen's business, and he is the one who comes out to price the job, not a salesman. A verified customer's 10 out of 10 on Checkatrade. The visit and the written quote are both free.