Loft insulation in Furzehill

The tank, since that is what people ask about. A cold water tank has spent its whole life sitting in a mildly warm loft. Put full depth underneath it and it is suddenly outdoors, which is how a tank that has never frozen freezes. So it gets a jacket, the lid gets one, the overflow and every run of pipework get lagging, and the ceiling directly beneath the tank is left thin on purpose so a little warmth still reaches it. The platform it stands on gets looked at while we are there. All of that is part of the job rather than an extra at the end of it.

Depth, and why the second run matters. Trussed roofs dominate around here and their joists are shallow, so one layer laid flush is barely half a system. So a second run of mineral wool is rolled out over the top of the timber, at right angles to the first, which is the part that stops a ceiling giving its heat away along every joist. Take the pair to roughly 270mm and you are at the u value Approved Document L wants from a renovated ceiling under Part L. Rockwool batts where a roll will not sit, glass wool on the roll everywhere else, loose fill where bracing makes a roll impossible, sheep wool if you want it, and rigid PIR board where the headroom simply is not there.

The eaves, which you cannot judge from the hatch. Material goes to the wall plate and no further. Vent trays sit in the rafter bays to hold the path above it open, so the material can still be taken right to the edge without shutting off the cross ventilation that runs soffit to soffit. Where old bitumen underlay meets soffits boxed in solid, the roof is choked before we arrive, and a ridge vent goes in ahead of any new depth at all. Get that wrong and you get condensation on the felt, wet material and black mould over the timbers, none of which announces itself until it has been going on a while. BS 5250 is the standard on damp in buildings, and it is worth knowing that interstitial condensation forms inside the layer where you will never see it.

Everything else that lives up there. Every recessed light gets a fire rated cover dropped over it. Wiring is lifted and clipped on top of the new depth instead of being left down inside it, since cable sitting in insulation runs warm. Storage is planned instead of lost: loft legs, a raised floor clear of the wool, and boarding only where you actually stand. The hatch is insulated and sealed, and the loft ladder tried against the raised floor before we go. Getting up and down gets priced at the survey too, because a roof over your head does not stop it being work at height. And in a roof converted years ago none of that applies. A room in roof, with its sloping ceilings and dormer cheeks, is insulated up at the rafters instead: rigid board cut into each bay, a second layer fixed beneath, every joint of the vapour control layer taped, and multi-foil quilt where the depth has gone altogether.

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 detached house with a trussed roof full of bracing, and an older farmhouse with no clean void over half the plan 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 Furzehill, Colehill, Holt, Wimborne Minster, Three Legged Cross and the BH21 lanes 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.