Insulation in Iwerne Minster

Topping up a loft over shallow joists. Nearly two in five dwellings in Iwerne Minster predate 1919, and on those cottages the ceiling joists are shallower than anything in a modern build, and often not evenly spaced. Filling between them and stopping there leaves you well short, and it leaves every joist working as a cold bridge straight through the layer. It goes in between and over: the first layer between the timbers, the second run across them at right angles so the joists disappear underneath it. Around 270mm of mineral wool eco roll is what it takes to bring a ceiling to the u-value of about 0.16 that Approved Document L expects when you renovate a roof.

Roofs with nothing under the tiles. A good many of the pre-war roofs in the village were never felted, so the underside of the tile or slate is what you are looking at from the loft. Those roof spaces have always been draughty, which is why they have got away with thin insulation for a century. Lay full depth in one and the air up there gets colder and wetter at the same time, so we keep the eaves clear with vent trays, check there is a way for air to cross the space, and never let the roll run out over the wall plate and choke the gap.

Under the oldest ceilings there is lime pushed through riven lath, which will carry insulation but not people and not a boarded floor. We work off crawl boards and keep the load light, and if you want storage it goes on a raised deck carried on legs off the joists rather than squashed down on the quilt. Compressed material stops working, and it is the single most common fault we find in a loft that has already been done once.

Several of the bigger detached houses here have a converted attic or a dormer, and there is no loft to lay a roll in, so it is rigid board work: PIR such as Celotex between the rafters with an air gap kept behind it, then a foil faced board under the rafters, or a multi-layer product like TLX where the depth simply is not there. Solid stone and brick walls have no cavity to fill, so the choice is internal wall insulation on the room face or external wall insulation, and in a conservation area with forty listed entries that decision is usually made for you. The post-war houses get a borescope before anyone quotes a fill.

The area is the easy part, so there is no rate per square metre. What sets the price is everything around it. A stone cottage with the hatch over a narrow landing, a bungalow with a hip end and no room to work at the eaves, and a detached house with a boarded loft full of storage are three different days before any material is bought. Old material has to be bagged and taken away first. Approved Document L sets what the work is expected to reach. Ask what finished depth is being laid, and whether the eaves, the hatch and the tank are in it.

We cover Iwerne Minster, Fontmell Magna and the Iwerne valley villages, down through Stourpaine to Blandford Forum on DT11, 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.