Wall insulation in Longham

The check that decides it. A nine inch solid wall and an early brick and block cavity are indistinguishable from the drive. So we drill a small hole in a mortar joint and put a borescope in: is there a gap, how wide, is it clear, is it dry, has anything been in it. On an exposed house we also look at the state of the outer leaf, because that is what stands between the fill and the rain.

Cavity wall insulation, and the choice of material. Bonded polystyrene bead is usually the right answer on an exposed Longham wall. It flows into the corners, it does not slump, and it is far less inclined to wick water across the gap than a fibre. Blown mineral wool is cheaper and perfectly sound on a sheltered elevation, which on a detached house often means only one or two of the four. Fill goes in from outside through drilled holes made good in matching mortar.

When we say leave it empty. A cavity that is under fifty millimetres, one with mortar droppings bridging the ties, a cracked or badly pointed outer leaf, or any sign of water already crossing, and filling it moves the problem inside. On the most exposed wall of an isolated house the honest answer is sometimes to repoint and repair first and insulate that elevation on the inside instead.

Internal wall insulation. IWI is the route for a solid wall and the fallback for a cavity we will not fill: insulated plasterboard bonded on, or batten and stud with mineral wool or PIR between, boarded and skimmed. Celotex and Kingspan buy more per millimetre, aerogel board suits a tight room. Reveals, threshold, floor junction and joist ends are wrapped, because the heat loss in a lined room concentrates at the edges.

External wall insulation. EWI is board on the outside face with a render carrier and a thin coat over it. On an exposed Longham house it does two jobs at once, insulating and weatherproofing, and it takes the thermal bridge out at eaves and corners. It thickens every reveal and pushes sills and rainwater goods outwards, so it is a bigger piece of work than a fill.

Old fill, and ventilation. A slumped cavity leaves a cold band at the head of the wall; a wet cavity carries penetrating damp inside and black mould with it. The borescope reads both and extraction comes first. Then the air: trickle vents, a working extract fan, any air brick that has been blocked. Insulating shifts the dew point and removes the draughts, so a taped vapour control layer and breathable materials keep interstitial condensation out of the build up.

Which wall you have. A clean, dry, empty cavity is usually filled in a day, the cheapest way there is to insulate a wall. A cavity filled years ago with fibre that has slumped or got wet may need extracting first, which is a much bigger job. A solid wall, found on the few older cottages in Longham, has no gap to fill, so it means boards on the inside or a system on the outside.

Exposure. A south west gable on an open Longham plot takes the driven rain. Bonded bead and mineral wool behave differently on a wall like that, and the wrong one bridges water across the cavity. The survey decides the material.

The junctions. For internal lining, window reveals, the floor junction and the eaves are where heat leaks out and where condensation shows if the detail is sloppy. That is slow work and most of the labour.

Access and disruption. Cavity fill is drilled from outside. A bungalow needs little more than a ladder and a low tower, while a two storey gable needs more, and the work at height rules set the platform. Internal lining is done room by room from inside.

Ask other quotes: has anyone looked into the cavity with a borescope? Which material and thickness, and why? Is ventilation addressed? Who makes good the plaster and decoration after?

We cover Longham from our base in Boscombe, 4.7 miles away, including the Ham Lane side, Hampreston and the BH22 addresses around them. For planning and for building control alike, the authority is Dorset Council.

Bournemouth Roofing & Building Ltd is registered in England and Wales, company number 15471719, and it is Thomas Hannen's company. He is the one who drills the test hole, looks into your cavity and prices the job. There is a verified customer's 10 out of 10 on Checkatrade. We charge nothing to come out, and nothing for the written quote with its items set out. Before you book a visit in Longham, you can read our customers' Google reviews, word for word, on our reviews page.

Most repairs in Longham 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.