Wall insulation in Stone, party walls and end gables
On a terrace the cavity does not stop at your boundary, so where the fill goes and who needs telling matter as much as which material it is.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
A good part of the housing around Stone is terraced or flats, which means a lot of these walls are shared. On a terrace or a maisonette the wall between you and next door is a party wall, and a cavity does not stop politely at your boundary. That changes the practical questions: where the fill goes, who has to be told, and which walls are actually yours to insulate.
What people ring about is straightforward. A cold end of terrace gable that is always the worst wall in the house. Mould appearing along the top of an upstairs wall. Or a flat where the owner wants the outside wall lined and is not sure whether the freeholder has to agree.
We start by reading the wall. One small hole and a borescope tells us the cavity width, whether it is clear and dry, and whether anything has already been blown into it. Then we look at the reveals, the threshold, the eaves and the joist ends. The site visit and the written itemised quote are both free.
The work
Shared walls, end gables and the cavity between them
End gables, which are the cold ones. A mid terrace loses heat through two walls; an end of terrace loses it through three, and the extra one is a whole gable with nothing warm on the other side of it. That is why the end house is always the coldest in the row, and why it is usually the wall worth doing first.
Cavity fill, and cavity barriers. Where the borescope shows a cavity that is wide enough, clear of mortar snots and dry, it is drilled and filled in a day. In a terrace the cavity often runs on past the party wall, so a barrier goes in first or your bead ends up warming next door. That is standard practice and it is also a fire separation matter, not just a tidiness one.
Telling the neighbours, and the Act. Work to a shared wall itself, cutting into it or fixing to it, is party wall territory and the Party Wall etc. Act sets out the notice. Filling your own outer cavity is usually not, but where the cavity is continuous it is still worth a conversation before the drill comes out rather than afterwards.
Internal wall insulation, IWI. On solid brick, or where the cavity is too narrow, the lining goes inside: insulated plasterboard bonded to the masonry, or a batten and stud frame filled with mineral wool. PIR laminate such as Celotex or Kingspan gets there in the least depth, with the vapour control layer taped so warm air cannot get behind it, per BS 8000-8.
External wall insulation, EWI. Boards, a render carrier and a render finish. On a terrace it is rarely one owner's decision, because the system has to stop somewhere and a single insulated house in an unrendered row looks exactly like what it is. Where a whole row or a whole block goes together it is the strongest option available.
Fill that has failed. Wool blown in years ago slumps and leaves a cold band under the eaves, which shows inside as black mould along the top of a wall. A wet cavity, where water crosses on a bridge, gives damp patches that follow the weather. Both begin with extraction, drilling and vacuuming the old material out, not with adding more.
Junctions, ventilation and draughts. Reveals, the threshold, the floor junction and the joist ends are where the heat loss is concentrated, and a thermal bridge left at any of them collects condensation whatever the u value beside it. Reveals take a thin board or aerogel. Then trickle vents, a working extract fan and clear air bricks, because airtightness without ventilation is how a warm house turns mouldy, and Approved Document F sets what is expected.
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.
This is Dorset Council territory, in the Pamphill parish. There is no conservation area covering the housing itself, and the listed entries around here are concentrated on the Pamphill estate rather than among the houses, so for most addresses this is a building control question rather than a planning one. Where an existing wall is upgraded, regulation 23 sets what the finished element has to reach under Part 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 mid terrace with one narrow side passage, an end of terrace with a full gable to the weather and a flat over a shop 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. We are eight miles away on the Wimborne side, so an address here is normally looked at within a day or two. The phone is answered 24 hours for emergencies; scheduled work runs Monday to Friday, 8am to 6pm.
Worth knowing
The wall you share, and the one that costs you
On a terrace it is easy to spend money on the wrong wall. The party walls have a heated house on the far side of them and lose almost nothing, so insulating them achieves very little except a narrower room. The front and back walls and, on an end house, the gable are where the heat actually goes. Any quote that prices the whole internal perimeter of a mid terrace is selling you square metres rather than warmth.
The shared cavity is the other thing worth understanding. In a lot of terraces the outer leaf runs on continuously behind the party wall, so material blown in at your end can travel, and a problem at your neighbour's end can travel back. That is why a cavity barrier goes in before the fill does, and why a straight conversation with next door before the work is worth more than a letter afterwards. On the flats, remember the outside wall is normally the freeholder's, so written consent comes before any drill or any board.
Who you are dealing with
A local firm you can check
We cover Stone, Pamphill, Cowgrove and the Wimborne edge, broadly BH21, under Dorset Council. 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
Stone questions we get asked
Should I insulate the wall between me and my neighbour?
Usually not. There is a heated house on the other side of it, so it loses very little. The front, back and any gable are the walls that cost you money.
Does cavity fill travel into next door's wall?
It can, where the outer cavity runs on past the party wall. That is why a barrier goes in first, and it is a fire separation point as much as a tidiness one.
Do I have to give my neighbour formal notice?
For work to the shared wall itself, yes, under the Party Wall etc. Act. For filling your own cavity, usually not, but a conversation first saves a lot of bother.
How long does it take, and can you work with a narrow side passage?
A normal fill is a day. A tight passage means barrowing and a smaller platform, so the access shows as its own line on the quote rather than disappearing into a rate.
Why is the end house always the coldest in the row?
Because it has an extra outside wall, and that gable takes the weather with nothing warm behind it. It is normally the first wall worth doing.
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Thomas comes out, borescopes the cavity, says which walls are worth doing and prices the work in writing. The visit and the quote are free.