Loft insulation in Yarmouth

More than a third of the homes on this side of the Island are bungalows, and a bungalow changes the arithmetic. Every room you pay to heat sits directly under one ceiling, so that ceiling carries almost the whole of the building's heat loss. Bring it up to depth and you feel it in every room at once. It shows on the heating bill, and it shows on an EPC as well. The catch is that the same roof is wide and low, so much of that ceiling sits under a shallow triangle nobody can stand up in, and the far corners are reached a length at a time from the middle outwards.

So we start at the outside edge and work back in. Where the rafters land on the wall plate the loft is at its tightest and at its most important. It has to take full depth and still leave an air gap for ventilation to get into the roof. Vent trays clipped between the rafters hold that gap open, and the wool is brought right up underneath them, so there is no cold band round the outside of every room and no blocked eaves either. Air then comes in low, travels the length of the roof over the insulation and leaves at the top, through a ridge vent where one is fitted. That is cross ventilation, and on a roof with no breathable membrane behind the tiles it is the whole of the system. Insulating the ceiling pushes the dew point up into the roof space, which is exactly why that gap has to stay clear.

The depth itself is simple. Wool goes in between the joists to begin with, then a second thickness is turned ninety degrees and run over the top of them, so every joist ends up buried. The two layers finish at about 270mm. Crossing the top run is what stops the timber acting as a cold bridge, and it is what actually moves the U value. Rolls of mineral wool, glass wool or rockwool, cover the open ground. Batts fit where a truss cuts the space into small bays, loose fill reaches under a low pitch where nothing else will go, and sheep wool is there if you would prefer it.

Getting on for a third of the housing here went up before 1919, and those roofs were cut on site out of rafters and purlins with no underlay behind the tiles at all. They breathe well, but wind moves through them freely, so material is laid to stay where it is put rather than unrolled and left. The ceilings beneath are often lath and plaster and will not carry a knee, so crawl boards go down before anybody leaves the hatch. Access is that one hatch, and working out of it is work at height whatever the ceiling is made of, so the ladder is set properly and the loft is lit.

The rest is the detail that gets missed. Wool that has settled, been compressed under a deck, gone patchy round old wiring or been contaminated where birds have left droppings is lifted, bagged and carried out, and so is anything missing for the last foot before the wall. Recessed lights and downlighters take fire rated covers rather than wool heaped over the fitting. Cables and wiring are lifted clear and laid on top. The tank and its pipework get lagging, because a loft that has just been done properly is a colder place than it was last winter. If you keep things up there, the deck is rebuilt on legs high enough that the wool underneath is never touched, and the loft ladder is adjusted to land on it. The hatch takes rigid board and a compression seal, because a bare flap of plywood leaks warmth and draws damp air after it.

Where the roof is already a room, none of that applies. Sloping ceilings and dormer cheeks are rafter level work. The air gap comes first, held clear above the board so the timbers can dry. Then PIR or Celotex cut between the rafters, a second board under them, and a vapour control layer taped at the joints. Multi-foil quilt does the job where a ceiling can spare almost nothing. Get it wrong and the damage is interstitial, which means condensation forming inside the build up where nobody can see it, and wet timber and black mould turning up long afterwards. Where the covering is coming off anyway, a warm roof over the deck is the better answer.

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 harbour cottage with a small hatch over a narrow stair, a post-war bungalow with a wide open loft, and a house with a fully boarded loft are three different jobs 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 Yarmouth, Norton, Thorley and the PO41 addresses around them, with the Isle of Wight 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.