Loft insulation in Hangersley

What is already down. Almost every loft here has something in it. Forty odd years of settling has taken the depth out of it, it is compressed flat along the routes people walk, patchy in the open middle and missing altogether where the roof gets low. Where it is dry and in one piece it stays and we lay over it. Where it is damp, black on the underside or contaminated with droppings it comes out, is bagged and leaves with us on its own line.

Material, chosen for the space. Mineral wool does most of it, as glass wool on the roll or as rockwool in batt form. Loose fill, blown or poured, works where the joists are at odd centres or the triangle is too tight to open a roll out in. Sheep wool is there if you want it. Where there is no headroom to give away, PIR rigid board goes in cut tight and taped, and a multi-foil quilt handles the shallowest last stretch.

Two layers, the second one crossways. One layer laid flush between the joists is where most lofts stop, and it leaves the timber conducting heat straight through the ceiling. So the first goes between the joists and the second is cross laid over the joists and turned through ninety degrees. Around 270mm all in, which is the thickness a Part L U value amounts to in practice and the single biggest cut in heat loss most of these houses have left to make.

The eaves, and what happens when they are blocked. The layer is carried to the wall plate and stops. Vent trays hold a clear air gap above it so cross ventilation passes right through the roof space, and where the eaves genuinely cannot be opened up a ridge vent is sometimes the answer. Seal them and the vapour that used to drift out sits under cold felt instead. Insulating moves the dew point, interstitial condensation forms inside the layer, and by February there is a wet layer and black mould over every rafter. A breathable membrane is detailed differently and works the same way.

Everything else in the roof. Recessed lights are hooded rather than smothered. Cables sit above the insulation rather than inside it, because buried wiring runs hot. A the cold water tank and its pipework are left in the cold and have to be lagged, with the patch under the tank left thinner on purpose. The hatch gets insulated and sealed. Where a roof has already been converted, a room in roof is a rafter level job, built as a warm roof, sloping ceiling and dormer cheeks included.

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 detached house with a loft ladder into a big open roof, a bungalow with a hatch on the landing, and a cottage where the only way in is a trapdoor over the stairs make three different mornings, and every one of them opens with work at height. 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.

The biggest slice of housing around here went up in the late 1960s and early 1970s, which is exactly when the trussed rafter took over from the roof cut on site. It is a good roof and a cheap one, and it is a nuisance to work in. Instead of a clear space with a purlin down the middle you get a triangle criss-crossed with webs and diagonal bracing, all of it doing structural work. None of it can be cut, notched or moved to make room for a roll, so the material gets fed through and trimmed to each bay by hand, on your front, which is time before anything is insulated.

Storage is where it bites. A trussed roof was never designed as a floor, so boarding straight across the ties is a bad idea twice over: it loads timber that was not meant to carry it, and it squashes the insulation flat to the depth of the joist. Loft legs solve the second half by standing a raised floor clear above the full depth, and we will tell you honestly how much of the roof will take a platform and how much of it should be left as insulation and nothing else.

We cover Hangersley, Hightown, Ringwood, Poulner, Burley Street and Ashley Heath, and the BH24 addresses around them, 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.