Loft insulation in Hyde

Every loft has an easy middle and a difficult edge. Where the rafters come down onto the wall plate the space narrows to nothing, and that is where three things all have to happen at once. The insulation has to reach full depth, the air gap above it has to stay open, and neither can be achieved by shoving wool in and hoping. Vent trays clip in between the rafters first to hold the gap, then the material is worked right up under them so there is no cold band running round the outside of every room. It takes longer than the rest of the loft put together and it is the first thing we would check on anybody's quote, ours included.

With the edges settled, the depth is straightforward. Between the joists first. Over them second, cross laid so the top layer runs at odds with the timber underneath, which is what stops the joists carrying cold down into the rooms. Roughly 270mm all in, the figure Approved Document L sets for a loft being renovated. Rolls of mineral wool, glass wool or rockwool, do the long runs. Batts drop into small bays, loose fill reaches where a roll cannot follow, and sheep wool is available. What it buys is a lower U value at ceiling level, and since more heat loss goes out that way than any other, the difference turns up on the heating bill before an EPC ever gets round to it.

Ventilation is the other half of the same detail. Cross ventilation enters at the bottom of the slope and finds its way out at the top, and a ridge vent is what gives it somewhere to go. A breathable membrane hands a modern roof a second route out, while an old bitumen felt underlay hands it nothing. Insulating the ceiling carries the dew point up into the roof space, so a loft that managed perfectly well for years can show condensation, wet wool and black mould on the timbers in one winter if the edges get packed.

Old material gets a verdict before anything new goes down. Anything compressed under a deck, contaminated where birds have left droppings, settled to half what it was, missing for the last foot before the wall, or patchy where somebody cut round old wiring comes out and leaves in the van. Sealing it under new work only hides interstitial damp where nobody will find it. Access is that hatch and nothing more, so crawl boards go down before anyone leans on a ceiling and the whole job is work at height from the moment the ladder goes up.

The rest is the detail. The cold water tank is lagged, and the pipework with it, because the roof space is colder after the job than before it. Wiring and cables go on top of the insulation. Fire rated covers go over recessed lights and downlighters. Where the loft is in use, legs carry the boarding above the wool, the loft ladder is reset to the new platform height, and the hatch is finished with rigid board and a draught seal. Where there is no loft floor at all, the work goes in at rafter level. Between the rafters, rigid board. Above it, an air path left open. Under them, another layer so the timbers are covered too. Then vapour control, taped, on the room side, with multi-foil kept for a sloping ceiling or a dormer cheek that cannot give up a millimetre.

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 cottage with a small hatch over the stairs, a farmhouse with a big open loft and no boarding, and a modern house with a trussed roof full of bracing are three different mornings before any material is opened. 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.

We cover Hyde, Frogham, Ogdens, Godshill and the SP6 addresses around Fordingbridge, with the New Forest National Park Authority for planning and New Forest District Council for 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.