Insulation in Longham

A second layer over the original loft. Three in five homes in Longham went up between 1945 and 1982, and the layer that went down when they were built is an inch or two of quilt pushed between the joists, with decades of settling taking the rest. It is rarely worth removing. It goes in between and over: fresh mineral wool eco roll between the timbers, then a second run at right angles across the top so the joists stop acting as cold bridges through the layer. Around 270mm all in brings a ceiling to the u-value of about 0.16 that Approved Document L asks of a renovated roof, and on most ceilings here that is one day.

Bungalow lofts, which are the big ones. More than a third of the housing here is bungalows. A bungalow has the same floor area as a house and roughly twice the ceiling under the roof, so the loft is where nearly all of its heat loss goes. The catch is the shape: a hipped roof closes down to nothing on all four sides, so the perimeter is tight and the eaves are easy to block by accident. Vent trays go in first, the quilt stops clear of the wall plate, and the corners get filled properly rather than being left as the gap nobody can reach.

Anything built here from the mid sixties onward is likely to have a trussed roof: shallow timbers with diagonal webs criss-crossing the space at ankle height. You cannot walk it, you cannot board it as it stands, and a second layer means working around every web rather than rolling out in straight runs. It is slower, and it is why a trussed loft and a cut roof of the same area are not the same job. Boarding straight onto the joists compresses the quilt to the depth of the timber, so we raise the deck on legs above the full depth and board the part you actually use.

Houses of this age were built with a cavity wall, and whether it was ever filled is a question for a borescope and not for a guess. Some were done decades ago with material that has slumped, some were never done, and some should not be. Where a wall turns out to be solid, an internal wall lining built to breathe is the honest answer, since external wall insulation changes the look of the house. A chalet bungalow or a converted attic is a room in roof: rigid board rather than roll, PIR between the rafters with an air gap kept clear above, a multi-layer quilt such as TLX under a sloping ceiling with no depth to give, a vapour control layer on the warm side and the dormer cheeks done at the same time. The flat roofed garages and rear extensions of this era have next to nothing in them, and the time to turn one into a warm roof is when the covering is being replaced.

A price per square metre tells you nothing. The area is the easy part. A bungalow with the hatch in the hall and a hipped roof at both ends, a chalet with the room already in the roof, and a detached house with a proper ladder are three different days before any material arrives. Boarding that comes up and goes back is time before a roll is laid. Approved Document L sets what the work is expected to reach. Ask what finished depth is being laid, and whether the hatch and tank are on the list.

We cover Longham, Ferndown, West Parley and Hampreston on BH22, down through Bearwood and across to Wimborne, and Dorset Council is the planning and building control authority for this address. 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.