Wall insulation in Merley
Most walls on this estate were filled within a few years of each other, so the question is what condition that old material is actually in.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
Most of this estate went up in the 1970s and early 1980s, which means most of these walls were filled in the same handful of years and that fill is now decades old. The useful question here is not whether to insulate a wall but what condition the last lot of material is in.
The calls follow that. A bedroom that has turned cold along the top of an outside wall. Damp patches on the weather side that were never there before. Or a house being sold, where a survey has flagged the cavity and nobody has actually looked inside it.
We look with a borescope through one small hole drilled in a mortar joint, take moisture readings on the inside face and walk round each elevation. Then a free written itemised quote, with the survey, any extraction, the system, the junctions and the making good on separate lines.
The work
Fill that has done thirty years, and what comes next
Reading the existing fill. The scope shows what is in the cavity, how far down it sits, whether it is dry and whether it is still packed against the inner leaf. Two faults turn up again and again on stock of this age: material that has slumped and left a void at the head of the wall, and material that has been wetting for years and stopped working long ago.
Slumped fill. Blown fibre settles under its own weight, particularly where it was installed thinly or where the wall has been knocked about by later work. The result is a warm band low down and a cold one along the top, which is why one wall of a bedroom feels different from floor to ceiling. It shows on a cold morning as a stripe of condensation before it ever shows on a meter.
Wet cavity, and extraction. Where water is crossing on the fill, penetrating damp appears inside on the weather face, black mould follows behind furniture, and no amount of internal decoration fixes it. The material has to come out. Extraction is done through drilled holes with a vacuum, the cavity is checked clear, the outer leaf is repaired and repointed where it needs it, and only then does anything new go back.
Refilling, and what with. A clear, dry cavity of decent width takes bonded polystyrene bead, which flows into corners, holds its position and does not wick water across the way an older fibre could. Blown mineral wool is still a reasonable answer on a sheltered wall. Fill goes in from outside through a pattern of drilled holes made good in matching mortar, and a normal house is a day.
Internal and external work. IWI is the fallback for a wall we will not refill: insulated plasterboard bonded on, or batten and stud with mineral wool or PIR between, boarded and skimmed, with Celotex, Kingspan or an aerogel board depending on the depth you can spare. Reveals, threshold, floor junction and joist ends get wrapped, because that is where the heat loss is. EWI puts board on the outside face with a render carrier and a thin coat, and takes out the thermal bridge at eaves and corners in one pass.
Ventilation. Insulating a wall shifts the dew point and takes away the draughts that were drying the house out, so trickle vents, a working extract fan and any air brick that has been blocked up belong in the same quote. A taped, continuous vapour control layer keeps interstitial condensation out of the build up. An EPC will move on the back of it, though the payback you feel is the airtightness.
How it runs
From your call to a written price
Same team from first visit to last, one person to ring, and no sub-contracting your work out to somebody you have never met. The quote is itemised, not a figure on the back of a card: the survey and any borescope check, the system and its thickness, making good around windows and doors, ventilation works, and disposal on separate lines, so you can compare it properly against anyone else's.
Nothing is left open or unusable overnight. The site is swept at the end of each day rather than the end of the job, and what comes out leaves with us. If something turns up once we start that nobody could have seen, you get a photograph and a price before we carry on.
Lining the inside of a wall is not development and needs no application, which Planning Portal guidance on insulation confirms; the outside face is a bigger question and Planning Portal guidance on external walls sets out when permission is needed. The listed entries on this side are concentrated on the Canford School estate rather than in the housing, and BCP Council keeps the listed entries. It stays notifiable work: regulation 23 means a renovated thermal element has to reach the Part L standard in Approved Document L, and building control take the U value and the ventilation together.
Cost
What decides the price of a wall insulation job
No rate per square metre, because the wall area is the easy part; what happens at every window, door and floor junction is not.
Getting to it. A detached house on the estate, a linked pair with a shared drive and a bungalow on the edge of it are three different jobs before a hole is drilled. Cavity fill is drilled from outside and a bungalow comes off a tower where a three storey gable wants a scaffold. Internal lining is worked room by room from inside, so it is your rooms rather than a platform that gets disrupted. The work at height rules still set the platform.
Which wall you actually have. A cavity that is clear and dry can be filled in a day. A solid wall cannot be filled at all, and has to be lined inside or insulated outside, which is a different job at a different price. A borescope through one drilled hole settles it, and no honest quote is written before that.
The junctions, not the field of the wall. Reveals at windows and doors, the floor junction, the eaves and any party wall are where heat escapes and where condensation shows up if the detailing is wrong. That work is slow, it is most of the labour, and it is the first thing a cheap quote leaves out.
Comparing quotes? Ask whether the wall has actually been checked with a borescope or just assumed, what system and what thickness is specified, how the reveals and floor junction are being detailed, whether ventilation is being addressed, and who makes good the plaster and decoration afterwards. Two quotes for the same job are usually two different jobs.
If damp has appeared
Damp or mould after a wall was insulated
Ring rather than use the form. Damp patches or black mould appearing on an outside wall after cavity fill or internal lining usually means water is tracking across the cavity, or warm air is reaching a cold surface at a junction. We look before we take anything out, because the fix depends on which of those it is. It is under six miles from us, so a BH21 address is normally seen within a day or two. The phone is answered 24 hours for emergencies; scheduled work runs Monday to Friday, 8am to 6pm.
Worth knowing
A whole estate whose walls were filled at the same time
Three quarters of the housing here dates from between the war and the early eighties, and the peak of it is the 1970s. That has an odd consequence. The walls did not just get built together, they got insulated together, in the grant rounds that followed, with the materials of the day. So when one fails it is rarely a one off. Neighbours compare notes about cold bedrooms and damp corners within a year or two of each other, and the reason is that the fill went in at the same time and has aged at the same rate.
The practical value of knowing that is what it saves you. If a house two doors down has had its cavity extracted and the material came out wet, that is a real reason to have yours scoped rather than assume. And if the fill in yours is dry, packed and sitting where it should, we will tell you that too and leave it alone. Extraction and refill is a proper job with real disruption, and it is not something to do on the strength of the year the estate was built.
Who you are dealing with
A local firm you can check
We cover Merley, Oakley, the Willett Road side and the BH21 addresses around them, with Bournemouth, Christchurch and Poole 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.
Questions
Merley questions we get asked
How do I know whether my old cavity fill has slumped?
A cold band along the top of an outside wall, or condensation showing as a stripe on a cold morning. The borescope confirms it by looking at where the material actually sits.
What does extracting cavity fill involve?
Holes drilled through the outer leaf and the material vacuumed out, then the cavity checked clear. It is dusty outside rather than in, and the holes are made good afterwards.
Can the cavity be refilled straight after extraction?
Only once it is dry and the outer leaf has been repaired. Putting new material into the same wet wall repeats the fault with a fresh invoice attached.
Is old fill always worth taking out?
No. Plenty of it is dry, packed and doing its job. We take it out when it has slumped or been wetting, and we say so plainly when it has not.
Is clearing and refilling a cavity one visit or two?
Two, normally. A day to extract the old material and check the gap is clear, then the refill once the wall has dried, with the drying time set by readings rather than a diary.
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Find out what your cavity is holding
Thomas comes out, scopes the wall, tells you whether the old fill is still working and prices the answer in writing. The visit and the quote are free.