Wall insulation in Christchurch
In the old centre most walls have no cavity to fill, and the conservation area decides whether the work can go on the outside face at all.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
A fifth of the houses in the town centre went up before the First World War, and most of those walls have no cavity in them at all. Where there is nothing to fill, the work goes on the inside face or the outside face, and in the middle of town only one of those two is a free choice.
People ring about a front room in the old streets that never feels warm, about a filled wall that has started showing damp on the weather side, or because a neighbour has had external work done and they want to know whether they can do the same.
We come and look before naming a system. One small hole drilled in a mortar joint and a borescope through it, moisture readings on the inside face, and a walk round to see which elevation catches the wind off the harbour. It goes into a free written itemised quote with the survey, the system, the junctions and the making good on their own lines.
The work
Old walls, post-war cavities, and the line between them
Settling what the wall is. Age is a hint, not an answer. A nine inch solid wall and an early brick and block cavity look identical once somebody has rendered them, so we drill and scope: is there a gap, how wide, is it clear, is it dry, is anything already in it. That is the fork in the road and it takes minutes.
Cavity wall insulation. Where the cavity is clear, dry and wide enough, it is filled from outside through drilled holes made good in matching mortar. Bonded polystyrene bead flows into the corners and holds position, which is what an elevation facing the water wants. Blown mineral wool is the older answer and still right on a sheltered wall. A wet or narrow cavity gets left alone, and we will say so.
Internal wall insulation. On a solid wall IWI is the practical route: insulated plasterboard bonded on, or battens and studs with mineral wool or PIR between, then boarded and skimmed. Celotex and Kingspan give more per millimetre; aerogel board earns its keep in a small room. The heat loss on a lined room is at the edges, so reveals, threshold, floor junction and joist ends are wrapped rather than butted up to.
External wall insulation. EWI means board on the outside face, a render carrier and a thin coat finish. It kills the thermal bridge at eaves and corners and keeps your rooms the size they are. It also changes the face of the building, so in the middle of town it is a planning question first and a technical one second.
Fill that has stopped working. Material settles, and a slumped cavity leaves a cold band at the head of the wall. A wet cavity is worse: driven rain crosses on the fill instead of running down the back of the outer leaf, and penetrating damp turns up inside, often as black mould in a corner. The borescope reads both, and extraction comes before any refill.
Ventilation and moisture. Insulating a wall shifts the dew point and removes 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, and on a pre-1919 wall breathable materials beat a sealed one. The EPC moves; 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.
Insulating the inside of a wall is not development and needs no application, which Planning Portal guidance on insulation confirms. The outside face is controlled here, because the town centre sits in the Christchurch Central conservation area and the council keeps the list. There are two dozen listed entries in the same streets, where consent covers internal work too, and BCP Council keeps the listed entries. It is notifiable either way: 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 rendered cottage on a narrow street, a post-war semi with a side path, and a 1980s house on an open plot 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 four miles from us, so a BH23 address is usually seen within a day or two, meter in hand. The phone is answered 24 hours for emergencies; scheduled work runs Monday to Friday, 8am to 6pm.
Worth knowing
The conservation area decides which face of the wall you may touch
Inside the Christchurch Central boundary, appearance is controlled. That has one blunt consequence for wall insulation: the outside face of your house stops being your own decision. External wall insulation thickens the wall by a hundred millimetres or more, buries the window reveals, alters the relationship between the openings and the face of the building and normally changes the material as well, which is a planning application rather than a choice of colour.
The inside face is a different story. Nothing about a dry lining is controlled by the conservation area, unless the building is listed, and then consent covers internal work too. So in the controlled streets we plan the job from the inside out and in the order that pays: the draughts first, because sash windows and suspended floors give up more than people expect, then internal lining on the rooms you actually sit in, built up so the old wall can still dry inwards. If external really is the right answer for your building, we will tell you what the application would involve rather than pretend the boundary is not there.
Who you are dealing with
A local firm you can check
We cover the town centre, Purewell, Stanpit, Somerford and the BH23 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
Christchurch questions we get asked
Can I have external wall insulation in the conservation area?
Only with permission. It changes the appearance of the building, which is exactly what the designation controls, so it goes in as an application rather than being assumed.
My house is listed. Does internal lining need consent?
Yes. Consent covers work inside as well as outside, and on a listed wall the build up matters more than usual because it has to let the fabric dry.
Why would you refuse to fill a cavity that is already there?
Because it is wet, too narrow, full of mortar droppings, or the outer leaf is in poor order. Filling any of those moves water inwards instead of keeping it out.
Does insulating one room work, or does it have to be the whole house?
Room by room works, as long as the junctions where the new lining stops are detailed properly. Left raw, that stopping point becomes the cold spot instead.
What is the disruption like when a room gets lined?
The room is out of use for a few days while the boarding and taping go on, then plastering and decorating follow. It is dusty, so we sheet and seal the rest of the house for it.
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Get the wall looked at before anyone quotes a system
Thomas comes out, drills one hole, reads the wall and prices the inside and outside options in writing. The visit and the quote are free.