Wall insulation in Sandford
Old cavity fill that has settled or gone wet, taken out and put right, with the wall checked by camera before anyone quotes, across Sandford and BH20.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
Most of Sandford went up in one long run between the late 1940s and the early 1980s, and a great deal of it was cavity filled in the same few years under the old grant programmes. That is why so many of the walls here have the same fault at the same time. If a neighbour has found slumped fill, it is worth having yours looked at.
The calls follow that. A cold band along the top of the upstairs walls. Mould in the same two corners every winter. Or a wall that has damp coming through on the weather side and a cavity full of wet fibre nobody has looked at since it went in.
We put a borescope through one drilled hole and show you what is in there. Then the options go into a free written itemised quote: leave it, extract it, refill it, or line the wall from inside. The site visit and the quote are both free.
The work
Fill that has settled, and what replaces it
The camera, before anything else. One hole in a mortar joint, a borescope on a stalk, and we can see the cavity width, what material is in it, how far down the top of it has dropped and whether the inner face of the outer leaf is wet. On a brick and block wall of this era the cavity is usually a nominal 50mm.
Extraction. Old fibre that has slumped or gone wet comes out through a drilled pattern with a vacuum and a whip, working from the bottom up. It is dusty, contained work and it takes a day on an average semi. What comes out is bagged and leaves with us. Nobody can tell you how long it will take without seeing what is in there first.
Refill, or not. Once a cavity is clear and dry, bonded polystyrene bead is what we use to refill. It flows into the awkward corners a fibre will bridge, it does not settle under its own weight the way loose fibre eventually does, and it sheds water rather than holding it. Where the outer leaf is cracked, blown or letting penetrating damp through, the wall gets put right first and the cavity stays empty until it is dry.
Closing the wall off properly. Before a bead goes in, the eaves are closed, every window and door reveal is checked, the threshold at the front door is dealt with and any hole cut for a flue or pipe is sleeved. That stops material ending up in the loft. A fill is normally covered by an independent scheme run separately from the installer.
Solid walls, and the few here. The older properties towards the Wareham end are nine inch solid brick with nothing to fill. Those take internal wall insulation, IWI in the trade: insulated plasterboard fixed back, or a stud and batten frame with mineral wool or PIR board such as Celotex or Kingspan between it, with an aerogel backed board where a reveal has no room to give. External wall insulation, EWI, means boards and a render carrier on the outside and a thin coat finish, which is the better U value and the bigger job.
Junctions and vapour. A lining is only as good as its edges. Reveals returned, the floor junction carried down, joist ends thought about, and a breathable vapour control layer taped continuously so the dew point cannot end up inside the build up as interstitial condensation. Miss it and you get a thermal bridge at every edge.
Ventilation. Extract in the kitchen and bathroom, trickle vents in the windows, air bricks kept clear at the base of the wall. Approved Document F sets the standard, and it matters more once airtightness improves.
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.
Nothing about a cavity fill, an extraction or an internal lining needs planning permission, which the Planning Portal page on insulation sets out. External wall insulation is the exception, because it changes the appearance of the building, and the Planning Portal guidance on external walls covers it. Dorset Council is the planning authority, there is no conservation area over Sandford and there are only four listed entries in the immediate area, so listed building consent is rarely in play. Building control still applies: regulation 23 means a renovated thermal element has to meet the Part L standard in Approved Document L.
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 1960s semi, a 1970s terrace and a bungalow with a rendered outer leaf are three different prices before anyone opens a wall. 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. Sandford is under ten miles from us, so a call from here is usually 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
Whole streets were filled in the same fortnight
Sandford is unusual in how tightly its housing sits in time. The bulk of it was built between the war and the early 1980s, with the biggest single burst in the late 1960s and early 1970s, and that has a second consequence nobody expects: the cavity insulation went in on the same programme too. Estates were done street by street, with the same material and the same crews, inside a few weeks of each other.
Material fails on a timetable. Loose fibre in a 50mm cavity settles under its own weight and under thirty years of the wall moving, and once the top of the fill drops below the upstairs ceiling you have a cold band of heat loss around the whole first floor. It shows up in the same corners house after house, which is what you would expect from a batch of work that went in together, and it drags an EPC down with it.
The practical upshot is that a neighbour's borescope is useful information. If the house next door has slumped fill, the odds are yours has too, and it is worth checking rather than waiting for the black mould to decide it. A short street can be looked at in one visit, and we will tell you which houses need extraction and which are fine, and roughly how long each would take.
Who you are dealing with
A local firm you can check
We cover Sandford, Holton Heath, Stoborough, Wareham and the BH20 addresses around them, with Dorset 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
Sandford questions we get asked
How can I tell if our cavity fill has slumped?
The usual sign is that upstairs feels colder than downstairs and mould appears near the ceiling rather than at the skirting. A borescope through one hole confirms it in minutes.
Can old cavity insulation be taken out?
Yes. It is extracted through a drilled pattern with a vacuum, working from the bottom up, and the material is bagged and taken away. On an average semi it is a day's work.
Should we refill the cavity afterwards?
Usually, in bead rather than fibre, but only once the wall is dry and the outer leaf is sound. If the outside is letting water in, we leave the cavity empty until that is fixed.
Is the same problem likely next door?
Often, yes. These estates were filled street by street with the same material at the same time, so faults tend to show up together. Checking two or three houses in one visit is the sensible way round it.
Will taking the old fill out make the house colder?
For the gap between extraction and refill, yes. If we are leaving the cavity empty on purpose we will say why, and put the money into an internal lining on the coldest wall instead, where the payback is better.
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Find out whether your cavity fill has dropped
Thomas comes out, puts a camera in the wall and tells you whether what is in there is still doing its job. The visit and the written quote are both free.