Loft insulation in Wimborne Minster

The boarded loft problem. Most lofts in this town are working storage. Cases, boxes, the tree, a spare bed. Whoever laid the floor screwed the boarding straight onto the joists, so the wool underneath has been compressed to a third of its thickness and is doing about a third of its job. What is left has usually settled, gone patchy in the traffic lanes and stopped short at the edges. Lifting that floor, clearing what is under it and building the depth back is the commonest single job we do here, and access is one hatch, so crawl boards go down before anybody moves off it.

Getting depth back under a floor. With the boards up and the old material bagged, wool goes between the joists and a second thickness is cross laid over the top the other way, so no timber is left standing proud to carry cold into the room below. Two layers, about 270mm finished. Approved Document L sets that as the standard for a loft being renovated. Open runs take rolls of mineral wool, sold as glass wool or as rockwool depending on the maker. Batts suit the bays between trusses, loose fill goes where neither will follow, and sheep wool is there for anyone who would rather have it. The point of all of it is a lower U value over the ceiling, because that ceiling is the biggest single route for heat loss in the house, and it turns up on the heating bill and on the EPC.

Then the floor goes back, higher. Loft legs stand on the joists and carry the boards clear above the finished insulation, so the raised floor gives you the storage and the depth underneath is left alone. The loft ladder is reset so it still lands on the platform. It costs a little more in materials and it is the whole difference between a loft that is insulated and one that only looks it.

The hatch. A loft hatch is a hole in a ceiling and it behaves like one. Warm damp air off the landing goes up round the edge of a bare plywood flap all day, and the draught coming back down is the one people feel on the stairs. It takes rigid board fixed to the top face and a compression seal round the rebate so it shuts onto something.

Air at the edges. The wool stops on the wall plate and never goes past it. That air gap is where the roof draws its air, and it needs it more once the ceiling is insulated, because the dew point moves up into a space that has just been made colder. Vent trays hold the gap open. Cross ventilation then does the rest, moving moist air up the slope and out under the ridge, helped by a ridge vent where one exists. Modern breathable membrane is forgiving. The bitumen felt underlay in the older streets is not. Pack the eaves and you get condensation, wet material and black mould on the timbers instead.

The things that live up there. The cold water tank is lagged and its pipework with it, since the loft is a colder place the day after than the day before. Wiring and cables come up onto the wool instead of lying underneath it. Fire rated covers go over recessed lights and downlighters. None of it is dear, and all of it is what gets left off a quote that looks cheap.

Flats and rooms in the roof. A third of the homes in the town are flats, many of them in older houses that were divided, and the roof space over a top floor flat usually belongs to the freeholder rather than to you. We will still survey it, and the quote is written so it can go to an agent or a management company without being done twice. Where the roof has been made into a room there is no loft floor at all. That is rafter level work: board goes between the rafters, an air path is kept open above it, another layer runs underneath, and the build up is closed with taped vapour control. Multi-foil earns its place only where a sloping ceiling or a dormer cheek is too shallow for anything else.

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 town centre terrace with a small hatch over the stairs, a top floor flat in a divided house, and a modern semi with a boarded loft are three different mornings before any material 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 Wimborne Minster, Colehill, Pamphill, Furzehill and the BH21 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.