Loft insulation in Merley

Topping up the original. An estate of this age was built with one layer of mineral wool laid between the joists, which was the standard of the day and is nowhere near the standard now. It has settled, it has been walked on, and it leaves every joist uncovered as a cold bridge. What is sound stays and is straightened out, the gaps are filled, then a new unbacked roll goes over the top at right angles to it. Cross laid, two layers reach about 270mm and the timber vanishes under them.

What comes out. Material that is wet, patchy, compressed under old boarding or contaminated by droppings is bagged in the loft and carried out rather than covered. So is loose fill that has migrated into the eaves. That clearing is its own line on the quote, and it is the line that is quietly left out of a cheaper price.

The edges. Insulation goes out over the wall plate and stops, with the air gap above it held open by a vent tray in each bay so cross ventilation can still run across the loft. Original layers on these houses almost always taper away in the last metre, which is exactly where the ceiling meets the outside wall. Push new material into the eaves to fix that and you close the roof up: condensation forms on the underside of the felt and mould follows on the timbers. A breathable membrane is more forgiving than old bitumen felt, but the eaves rule is the same.

Services that were fitted afterwards. Because the insulation went in first and everything else came later, cabling on these houses often sits on top of the wool or is half buried in it. It gets lifted and clipped above the new layer, since wiring buried in insulation runs hot. Recessed lights added over the years get fire rated covers, and the cold water tank and its pipework are lagged and given a lid once the loft is properly on the cold side.

Storage and roof rooms. If the loft is used, boarding goes on loft legs as a raised floor so the full depth stays uncompressed, with a platform at the top of the loft ladder and an insulated, draught sealed hatch. Where a house has a room in the roof, a dormer or a sloping ceiling, the work moves to rafter level: rigid board such as Celotex cut between the rafters with the air gap kept open above, PIR beneath, taped so the vapour control is continuous. That is a warm roof build up and it is quoted on its own.

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 detached house with a landing hatch and a drop down ladder, a bungalow with the opening in a hallway ceiling, and a loft already boarded out and in daily use are three different half days before any material goes down. 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.

Nearly half the houses in Merley went up in the 1970s and early 1980s, and most of the rest are not far off it. They were built to the same details by the same hands within a few years of each other, so the lofts are near enough identical: the same shallow original layer between the joists, the same small unsealed hatch, the same tank sitting in the middle, and the same last metre at the eaves where nothing ever quite reached.

That makes a quote predictable and it makes comparing two of them easy. The shape of the work is always keep what is sound, clear what is not, cross lay over the joists, trays at the eaves, lag the tank, seal the hatch, and lift the boarding onto legs if you want to keep using the space. If a neighbour has had theirs done, the useful question is not what it cost but whether the edges, the hatch and the tank were in the price. As for the listed buildings people ask about, the entries near here are concentrated on the Canford School estate rather than in the housing, so they have no bearing on an ordinary Merley loft.

We cover Merley, Broadstone, Canford Magna, Corfe Mullen, Wimborne and the BH21 addresses around them, with BCP 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.