Loft insulation in Iwerne Minster

Nothing in an Iwerne Minster cut roof repeats. The rafters were pitched on site with purlins running through the middle of the space, so you can stand up in most of it, but the ceiling joists below were cut by hand and their spacing wanders from one end of the run to the other.

Roll does not like that. It bridges the narrow bays and leaves a gap in the wide ones, so the first layer usually goes in as rockwool batts or as mineral wool roll cut to each bay, friction fitted tight to the timber on both sides. Where the joists sit close together and there is no room to open anything out, loose fill poured in and levelled does what a roll cannot.

What you find first in an Iwerne Minster loft is rarely bare timber. Something went down decades ago, and by now it is compressed flat wherever anyone has knelt, patchy across the middle, missing altogether along one side and full of holes where a cable or a pipe crosses. Sound wool is worth keeping: it gets teased apart, straightened between the joists and covered. Anything contaminated with droppings, anything wet under a slipped tile, and granular fill drifted into the corners is bagged where it lies and carried out.

The ceiling under all this in an Iwerne Minster house is often lath and plaster, and lath and plaster will not take a knee. So the work runs off boards spanning the joists, moved along as we go, and material is carried out from the hatch rather than dragged across the tops of the timbers. Where the roof drops away over a back addition the space becomes a crawl, and that stretch is priced by the time it takes, not the floor area. Getting up there is work at height even indoors, so the ladder and the hatch are settled at the survey and anything you store up there comes down before we start.

With the base even, the second layer goes on and it runs the other way. Cross laid over the top of the joists instead of between them, so the timber is buried and stops carrying heat straight down into the plaster. That is the layer people leave out, and it is the one that moves the U value. Two layers to about 270mm is what a renovated ceiling is expected to reach under Part L, set out in Approved Document L, and on a house with solid walls it is the cheapest thermal work left in the building. Glass wool, rockwool, roll or batt, sheep wool if you would rather have a natural fibre: the choice comes from the shape of the loft, not from the label on the packet.

Then the perimeter and the fittings, which is where the hours actually go. Insulation is carried out over the wall plate and stopped there, with a vent tray at every rafter holding an air gap open so cross ventilation still runs soffit to soffit. Choke that gap and the dew point moves into the structure, interstitial condensation forms on the underside of the felt where nobody can see it, and black mould creeps down the rafters by the end of the winter; BS 5250 is the code that deals with moisture in a roof, and it is worth knowing that the risk is well understood rather than bad luck. A ridge vent or a run of tile vents takes the job on where the eaves cannot be opened, and a breathable membrane changes the detail rather than the requirement. Recessed lights take fire rated covers. Every cable is lifted and clipped above the new layer instead of being buried in it. The cold water tank and its pipework get lagging now they sit in properly cold air, with nothing laid underneath the tank. The hatch has a board fixed to its back and a draught seal round the lining, loft legs carry a raised floor if you want to keep using the space, and the loft ladder is checked against the new height. Where the roof was turned into a room years ago the job moves to the rafters instead: PIR rigid board such as Celotex cut between them with the air gap kept above, a taped vapour control layer behind the plasterboard, and multi-foil quilt in the sloping ceiling and the dormer cheeks where there is no depth left to give.

A loft is not priced by the square metre either. The clear middle of it is quick, and the time goes on the edges and the awkward bits.

Getting up and moving about. A hatch above the stairs, a space so low you work on your knees, or boards that have to be lifted and relaid all take hours before any wool goes down.

What is there already. Old insulation that has flattened or turned to dust is bagged and carried out first. If the loft is used for storage, emptying it and putting everything back is part of the job.

How the roof is built. A traditional cut roof in an older village house, with purlins and struts, is slower to work round than a modern trussed one, though trusses have their own diagonal bracing to thread past.

The eaves and the fiddly parts. Keeping air moving at the eaves, getting full depth right into the corners and round the hatch, and protecting downlights take most of the labour. Approved Document L sets the standard the work is aimed at.

Ask any other firm how deep the wool will be, whether the old material goes, whether the eaves stay ventilated, and whether the hatch and pipe lagging are in the price.

From Boscombe to Iwerne Minster is 20.8 miles. We insulate lofts in the village and in Shillingstone, Child Okeford, Fontmell Magna and Blandford Forum, across the DT11 addresses around them, where planning and building control rest with Dorset Council.

Bournemouth Roofing & Building Ltd is the company, registered in England and Wales, company number 15471719, and its owner is Thomas Hannen, who goes up into your loft to price the job himself. We have one verified customer's 10 out of 10 on Checkatrade. The visit and the quote are free, and the quote is written and itemised. Before you book a visit in Iwerne Minster, you can read our customers' Google reviews, word for word, on our reviews page.

Most repairs in Iwerne Minster need no application at all. What decides whether a change to the outside of your house does is who the council is, whether a conservation area or a listing applies, and whether the place sits in a protected landscape.