Loft insulation in Lytchett Matravers

The boards come up first. A loft gets boarded for the suitcases and the Christmas box, the boards go down straight onto the joists, and whatever is underneath spends the next twenty years compressed to nothing. So they come up, what is under them is teased back open and straightened, and the floor goes back on loft legs standing above the finished depth. You keep the storage and gain the depth, which is the whole reason for doing it that way round.

Depth, and the run that does the work. The layer between the joists is half a system on its own. A second run goes on top of the joists rather than between them, crossing the first at right angles, and that is what stops the timber carrying heat out through your ceiling. The pair of them at about 270mm is the u value Approved Document L expects after a renovation, under Part L. Mineral wool does most of it: glass wool as a roll, or rockwool as a batt where the bays are awkward. Loose fill for anywhere the bracing leaves no room to open a roll out. Sheep wool if you ask. Rigid PIR board once the headroom is gone, and multi-foil quilt after that.

The eaves are not storage either. People push boxes and old material out into the eaves and close off the only path the roof has to breathe through. The new layer stops on the wall plate, a vent tray in every bay holds the gap over it open, and the cross ventilation carries on running soffit to soffit. Old bitumen underlay over solid boxed soffits is a roof that is choked already, so a ridge vent is fitted before a single roll is opened. The sign it has gone wrong is condensation on the felt and black mould across the timbers, and BS 5250 is the code covering how moisture ought to be managed in a building. Interstitial condensation will have been forming inside the layer for months before any of that becomes visible.

The hatch, the ladder and anything wired. A sealed loft floor is undone by an open hatch, so the hatch itself gets insulation on the loft side and a draught seal round the frame, and the loft ladder is tried to make sure it still swings clear of the raised floor. Recessed lights are boxed over with rated covers. Wiring gets dressed on top of the new depth rather than left underneath it, since cable packed into wool runs warm. The cold water tank and everything plumbed to it are out in the cold now, so lagging goes on. How we reach the loft is settled at the survey: indoors or not, this is work at height. And where the roof is already a room none of this is the answer. A room in roof is done at the rafters: rigid board in the bays, more of it fixed below, and a vapour control layer taped through so the dew point never reaches anywhere it could wet the structure. Sloping ceilings and dormer cheeks are all part of that same layer.

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 bungalow with the hatch in the hall, a fully boarded loft that has to come up and go back, and a chalet with rooms already in the roof are three different jobs. 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 Lytchett Matravers, Lytchett Minster, Upton, Organford, Sturminster Marshall and the BH16 addresses around them, with Dorset Council for planning and 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.