Loft insulation in Crossways

This is the part worth understanding before anybody quotes you. A loft is warm because your house leaks heat into it, and that warmth is what has been keeping the roof timbers dry. Insulate the ceiling properly and the space above goes cold, the dew point comes up with it, and the underside of the roof becomes the coldest surface in the building. Household moisture that used to drift away now finds it. That is where condensation, wet material and black mould on the timbers come from, and it is why depth on its own is only half a job.

So the air path is dealt with first. Insulation stops on the wall plate and never goes past it, and the air gap above is held open with vent trays clipped between the rafters so nothing pushed into the eaves later can close it. Cross ventilation is the name for what happens next: in at the bottom, up the slope, out under the ridge, with a ridge vent widening the exit where one is fitted. A modern breathable membrane gives a roof a second way out. Bitumen felt underlay gives it none, which is why on an older roof the eaves are the whole system rather than part of it. Any bathroom fan discharging into the loft gets ducted out where it belongs, because nothing wets a roof space faster.

Then the depth. Wool goes down between the joists to start with. Then a second thickness is turned across them, so the timbers end up under the insulation instead of poking through it, and the two layers finish at about 270mm. the Approved Document is where that figure comes from. Rolls of mineral wool, glass wool or rockwool, do the open runs. Batts go into the bays truss bracing creates, loose fill reaches a shallow pitch where a roll will not follow, and sheep wool is there if you would rather. What you are buying is a lower U value over the ceiling, which is the biggest single route for heat loss out of a house and shows on the heating bill before it shows on an EPC.

Whatever is already up there is dealt with before any of that. Patchy wool round the wiring, wool contaminated where birds have been in and left droppings, wool compressed under a floor, wool settled to nothing, or wool missing altogether for the last foot before the wall: all of it goes into bags at the hatch and out to the van. Covering it over hides interstitial damp in the middle of the build up where nobody will see it. Access is that one hatch, crawl boards go down before anyone puts weight on a ceiling, and it is work at height from the first rung of the ladder.

The last of it is what you use the loft for and how you get in. The cold water tank and the pipework running to it are lagged, since the space is colder now than it has ever been. Wiring and cables sit on top of the wool. Fire rated covers go over recessed lights and downlighters. Storage stays: loft legs lift the boarding above the finished depth, the deck is refitted, the loft ladder is reset onto the platform, and the hatch gets rigid board and a seal. Where the roof is already a room, the work moves to rafter level. Board goes between the rafters, PIR or Celotex, with the air path above it left open. A second layer runs under the rafters, the room side is taped to control vapour, and multi-foil is kept back for a sloping ceiling or a dormer cheek with nothing left to give.

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 1970s bungalow with a landing hatch, a terrace with a small hatch over the stairs, and a detached house with a fully boarded loft are three different mornings before a roll 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 Crossways, Woodsford, Moreton and the DT2 addresses out towards Warmwell, with Dorset 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.