Wall insulation in Woodlands

The camera, and what it finds. Mortar snots on the ties bridging the gap. Debris and dropped mortar sitting in the bottom of the cavity. A gap of 40 or 50mm where the plans said more. Ties that have corroded and expanded, sometimes enough to lift the outer leaf and start cracking the joints. None of that is visible from either side of the wall.

Cavity trays, or the lack of them. Over every window, door and abutment there should be a sloped tray taking water back out to weep holes. On a lot of Woodlands houses of this age there is nothing. Fill a wall with no trays and any water crossing the cavity has an unbroken path to the inner leaf, which is how a dry house becomes a damp one.

What goes in, and why. Where the cavity is clear, dry and wide enough, bonded bead is the safer material on an older brick and block wall: it flows past obstructions, gets into a narrow gap and does not slump later. Blown mineral wool suits a wide, clean, sheltered cavity. Drilled from outside on a grid, filled, holes pointed to match, a day for most houses. Part L sets what the finished wall should reach.

What should not be filled. A wet cavity, one bridged with mortar, one full of rubble, one under about 50mm, or a wall with no trays. On those the fill saves a little heat loss and buys a large risk of penetrating damp, and we would rather lose the job than do it.

Fill that has already failed. Mineral wool blown in decades ago can settle and leave the top metre of the wall empty, which shows up as a cold band under the eaves. Bead can escape through a hole in the inner leaf. Both come out through drilled holes, the wall is dried, and we give an honest view on whether it goes back.

Solid walls and single skin. The older cottages and the odd converted outbuilding have nothing to fill and take internal wall insulation or external wall insulation instead. IWI is insulated plasterboard or PIR such as Celotex or Kingspan on a batten or stud frame with taped joints and a continuous vapour control layer, or wood fibre and lime where the wall must stay breathable so the dew point sits somewhere that can dry.

Reveals and junctions. Filling a cavity leaves the reveals, the threshold, the floor junction, the eaves and the joist ends as cold bridges, and those strips are where condensation and black mould appear. Shallow reveals take an aerogel laminate. Houses of this period rarely have anything at the reveal at all.

Ventilation. Trickle vents, working extract fans and air bricks kept clear, to the rates in Approved Document F. Better airtightness with no ventilation just moves the problem.

Thomas comes out, looks at the brickwork, drills one small hole and puts a borescope in to see what the cavity holds, then prices it himself. Where a fill suits, it should go in through a registered installer who issues a CIGA certificate, so ask for it.

The written quote sets out the survey and borescope check, the system and its thickness, making good round windows and doors, ventilation works, and disposal. The fifties and sixties houses in Woodlands mostly have cavities, often narrow ones, and some were filled years ago with material nobody can name. The pre-1919 cottages have solid walls, which cannot be filled and need lining inside instead. Drill holes are filled to match the mortar, rooms being lined are sheeted, and waste leaves with us. If fill already in the wall is wet or has slumped, we show you photographs and a figure before carrying on.

Woodlands lies inside the Forest North East Conservation Area, so anything that changes the outside face of a wall is a question for the National Park Authority here; the interactive property map shows what covers your address. A cavity fill and internal work are not development, per the Planning Portal’s insulation guidance, and regulation 23 brings New Forest District Council building control in once more than half a wall is renovated.

Damp patches or black mould on an outside wall after cavity fill or lining usually mean rain is tracking across the cavity, or warm air is meeting a cold spot at a junction. Keep the room aired and note whether the damp shows high or low on the wall, and after which weather.

Phone 07435 839745 rather than using the online form. Where nobody answers, we ring back as soon as we are free. On the visit we check the fill with a borescope and look at the junctions before anything is taken out, because the fix depends on the cause. Scheduled work runs Monday to Friday, 8am to 6pm.

Call now: 07435 839745

The largest single building period around Woodlands was 1955 to 1964, about one home in five, alongside older cottages and inter-war houses, and that is a specific and slightly awkward vintage for wall insulation. Cavities existed by then, but the details that make them work were not yet routine. Trays over the openings were often left out. Workmanship on keeping the gap clear varied enormously. Wall ties were mild steel with a coating that has had sixty years to fail.

None of that means the walls cannot be insulated. It means the survey is the important part, and the answer differs house to house on the same road. Two identical looking bungalows built by the same firm in the same year can come back with one clean 60mm cavity and one half full of dropped mortar with no tray over the front door. There is no way to know which is which from the outside.

The other local point is shape. This is bungalow and wide fronted detached country, so the external wall area per room is high compared with a two storey house, which means the wall is a bigger share of your heat loss and a successful fill is worth more here than the same fill on a town terrace. Where the cavity will not take one, the money is better spent on the loft and the draughts than on lining every room.

Nearby places we also cover for wall insulation, with straight-line distances from Woodlands, and the other trades we offer in Woodlands itself.

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