Wall insulation in Merritown

Before the wall at all: the ground it stands in. Raised soil levels, a path laid over the damp course, an air brick blocked up, a gulley that stopped taking water years ago. Every one of those pushes moisture into the foot of a wall. Insulate over the top and it stays there, then reappears indoors as damp and black mould. Approved Document C starts at the ground, and so does an honest wall quote.

The bottom metre. Meter readings go on inside and out on a Merritown wall first, because this is where the answer usually lies. Staining, salting, a skirting that has gone soft, a floor junction reading wet. Nothing goes on a wall in that condition. Fix the cause, let it dry, take the readings again.

Then into the wall, twice. A nine inch solid wall and an early brick and block cavity are indistinguishable once render is on, so we drill and scope. On low ground the scope goes in high and low on the same elevation, because a cavity can be bone dry under the eaves and sodden a metre off the ground. Gap or none, what width, clear or fouled, wet or dry, empty or filled.

Mid wall, where a cavity fill can go. Clear all the way down, dry all the way down, wide enough: that is the test for a Merritown cavity. Material then goes in from outside on a drilled pattern made good in matching mortar. Bonded polystyrene bead travels into corners and holds position, which suits a weather elevation. Blown mineral wool is the older answer and still right where a wall sits sheltered. A day on a normal house.

The inside face. Internal wall insulation answers a solid Merritown wall, and answers any cavity we have declined to fill. Insulated plasterboard bonded on, or batten and stud carrying mineral wool or PIR, boarded and skimmed. Celotex and Kingspan give more per millimetre; aerogel board suits a small room. Reveals, threshold and joist ends are wrapped as standard, and the floor junction gets particular attention on this ground, because that is the one place where heat loss and moisture meet.

The outside face, and where it has to stop. External wall insulation is board on the outer face with a render carrier and a thin coat over it, wrapping the building in one pass and lifting the thermal bridge off the eaves and corners. Down at the bottom it must finish cleanly above ground level on a proper base track and bead. Take it into wet soil and the whole system wicks. Reveals, sills and rainwater pipes move outwards with it.

The head of the wall, and the air in the house. Fill that has slumped in a Merritown wall shows as a cold band up there; a wet cavity carries penetrating damp through instead. Both read off the borescope and extraction comes first. Then ventilation: trickle vents, a working extract fan, air bricks kept clear. Insulating moves the dew point and takes away the draughts, so a taped vapour control layer and breathable materials keep interstitial condensation out of the build up.

Wall insulation is not priced per square metre here. The open face of a wall is quick work; the edges take the time.

What the borescope finds. An empty, dry cavity is a short job from outside. A solid wall has no cavity to fill, so it is lined inside or wrapped outside, which is a bigger job at a bigger price. Until someone has looked inside, any figure is a guess.

Weather and wet ground. The south west face at Merritown takes the driven rain, and the surface water risk on this ground is high. Fill on an exposed wall that already lets water across can carry damp to the inside, so exposure is judged before fill is suggested, and BS 8104 is how it is assessed.

Reveals and junctions. Window and door reveals, the floor junction and the eaves are where heat leaks out and where condensation forms when the detail is poor. That slow work is most of the labour, and the U-value on paper means little if it is skipped.

Access. Fill on a bungalow comes off a ladder or a tower. A two storey gable needs more, and the work at height rules set what.

Ask anyone quoting: did they look inside the wall, or assume? What system and what thickness? How are the reveals and the floor junction handled? Who makes good?

From our base in Boscombe, Merritown is 3.6 miles away, near the airport in Hurn parish, BH23. Bournemouth, Christchurch and Poole Council handles planning and building control here, as it does in Bournemouth and Christchurch.

Bournemouth Roofing & Building Ltd is the company, registered in England and Wales, company number 15471719, and Thomas Hannen, its owner, does the borescope check and writes the price himself. A verified Checkatrade customer gave us 10 out of 10. The site visit and the written quote, with every item listed, cost nothing. Before you book a visit in Merritown, you can read our customers' Google reviews, word for word, on our reviews page.

Most repairs in Merritown 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.