Loft insulation in Winfrith Newburgh

Start where the warm wet air gets in, because everything after it depends on that. A loft hatch with a bare board and no seal is a hole in your ceiling, so it takes insulation on its back and a compression seal round the frame. Recessed lights are the other route up, and each one gets a fire rated hood dropped over it instead of wool packed round the fitting. Bathroom and kitchen extractors that were never taken out through the roof get ducted properly, insulated along the run and finished at a tile vent, because a fan blowing into a roof space is a kettle with the lid off.

Next the air path, before any material arrives. The new layer is carried right out over the wall plate and stopped there, with a vent tray pushed up between each pair of rafters to hold the gap open above it. That keeps cross ventilation moving from one soffit to the other and lets the roof dry itself out. Where the soffits are boxed solid, or old bitumen underlay has been used instead of a breathable membrane, a ridge vent or a run of vent tiles does the same work. Approved Document F is the standard. The thing it is protecting you from is interstitial condensation: shut the eaves and the dew point moves inside the layer, out of sight, where wet wool and black mould get on with it long before anybody opens the hatch.

Only then does the depth go in. Whatever is between the joists gets shaken back open, straightened and its gaps closed. Over the top goes a second run of mineral wool roll, laid across the joists at a right angle to the first, and that is the run which buries the timber and stops a ceiling giving up its heat in stripes. About 270mm all in is what a renovated ceiling is asked to reach for its u value under Part L, and Approved Document L is where that sits. Glass wool roll suits the open bays, rockwool batts suit hand cut joists that wander, loose fill goes where bracing will not let a roll open out, and sheep wool if you would rather have it.

The rest is finished on the same visit. Cables are lifted out of the wool and clipped over the top of it, since buried wiring runs warm. A cold water tank and its pipework are on the cold side of everything now, so they take a jacket and lagging, with the ceiling under the tank left thin on purpose. If you store anything up there the boarding comes up and goes back on loft legs above full depth, and the loft ladder is checked so it still drops clear of the raised floor. Where the roof is already a room, none of that applies: sloping ceilings and dormer cheeks want rigid PIR board cut tight between the rafters with an air gap held above it, a second layer beneath and every joint taped. That is a warm roof, and it is a careful day rather than a morning. Multi-foil quilt is for the stretches with no depth left at all.

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 the hatch over the stairs, a bungalow with a wide open loft, and a house 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 Winfrith Newburgh, Wool, West Lulworth, Coombe Keynes, Warmwell and the DT2 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.