Wall insulation in Corfe Castle
Solid stone walls that cannot be filled, thin internal linings where a room can spare the space, and straight advice on when to leave the wall alone, across BH20.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
The grey stone houses in Corfe Castle are solid wall. There is no cavity behind that Purbeck stone, so cavity insulation is not a product anyone can sell you here, and on the older properties in the village the right answer is often to leave the wall as it is and put the money into the things that actually change how the house feels.
The three calls we get are a cold north facing room in a cottage, a request to line one wall before a room is redecorated, and a newer house off the main street where somebody wants to know whether the cavity is worth filling. Those are three different jobs and only one of them involves a drill.
We come out and work out which you have. Where a lining makes sense we set it out on paper first, because on a small cottage room the thickness matters. The visit and the written itemised quote are both free.
The work
Solid stone, and the small things that beat it
Working out the wall. Wall thickness measured at a reveal, the bond looked at, and where a house has a later extension or a rear wing we drill one hole and borescope it, because plenty of cottages here are stone at the front and brick and block at the back. Two halves of one house can want opposite treatments.
Internal wall insulation, done thinly. A batten frame packed to line with mineral wool or PIR board, Celotex or Kingspan, and boarded over, or insulated plasterboard fixed back to the masonry. On a rubble wall the batten route wins because the background is not flat. In a cottage the constraint is space, so we often use less thickness than a specification sheet would and accept a poorer U value rather than lose 100mm from a tight room.
Where thickness cannot be given up. Around a staircase, in a hall or on a reveal with an old frame close to the face, an aerogel backed board gets a useful improvement into 20 or 30mm. It costs more per square metre and it is the right call in exactly those places, not across a whole elevation.
The junctions, which is where it goes wrong. Reveals returned, the lining carried past the floor junction, joist ends considered before anything is sealed, and the party wall thought about in a terrace. A wall that simply stops leaves a cold bridge at every edge, and black mould turns up on the edge rather than the middle. The vapour control layer is taped continuously, and on old masonry we prefer a breathable build up so the wall dries inwards rather than holding moisture at the dew point.
Cavity fill on the newer housing. The post war houses do have a cavity. Clear and dry, it takes bonded bead or blown mineral wool in a day, cuts the heat loss through that wall sharply and the payback is short. Slumped or failed fill is extracted through drilled holes and either replaced or left out. A fill is normally covered by an independent scheme run separately from the installer.
What we would talk you out of. External wall insulation on a stone elevation in the village: the boards and render carrier bury the stone and the application will fail. Injected damp courses sold as a cure for condensation. And lining a wall that is wet from a blocked gutter or a cracking cement render, because that boards over a fault rather than fixing it, and a failed render behind a lining is a wet cavity you cannot see.
Ventilation, and draughts. Extract in the kitchen and bathroom, trickle vents in the windows, air bricks kept clear. Approved Document F sets what the ventilation has to do, and tightening a house without it is how mould starts.
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.
Corfe Castle Conservation Area covers the village and there are 134 listed entries in the parish, which is unusually dense. That matters more here than almost anywhere: listed building consent is needed for internal alterations as well as external ones, so lining the inside of a wall in a listed cottage is a consent question, not a free choice. Dorset Council is the authority. On unlisted houses internal work needs no planning permission, as the Planning Portal page on insulation confirms, while external insulation does, under the Planning Portal guidance on external walls. Building control still applies through regulation 23.
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 stone terraced cottage on East Street, a detached house off the Wareham road and a post war bungalow are three different surveys. 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. Corfe is under ten miles from us and we are through the village most weeks. The phone is answered 24 hours for emergencies; scheduled work runs Monday to Friday, 8am to 6pm.
Worth knowing
In a listed cottage, the inside is controlled too
Most people know a conservation area controls what the street sees. Fewer know that listing works differently, and in a village with 134 listed entries that catches a lot of houses. Listed building consent covers the whole building, inside and out, so battening out an internal wall, boxing in a reveal or removing an old plaster finish can all need consent even though nobody outside will ever see it.
That changes the order of work rather than ruling it out. Before anybody applies for anything there is a list of things that are not controlled and usually worth more: draught proofing around doors and floorboards, secondary glazing, and a cover on a chimney no longer used. In a stone cottage those together cut more heat loss than 50mm of board on one wall.
Where a lining genuinely is the answer, the application is a reasonable one and we will set out what is proposed so it can be judged: the build up, the thickness, what happens at the reveals and what existing finish is being kept. What we will not do is board over lath and lime plaster in a listed cottage and hope nobody notices, because that is somebody else's problem in ten years and it is your name on the building.
Who you are dealing with
A local firm you can check
We cover Corfe Castle, Church Knowle, Kingston, Stoborough and the BH20 addresses around them, 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
Corfe Castle questions we get asked
Does a stone house in Corfe have a cavity?
The older ones do not. Purbeck stone walls are solid, often 500mm or more thick, and there is nothing inside to fill. Later extensions and post war houses in the village are a different matter.
Do we need consent to insulate a wall inside a listed cottage?
Very possibly. Listing covers the interior as well as the exterior, so a new lining, a changed reveal or the loss of an original plaster finish can all need listed building consent. Ask Dorset Council before ordering materials.
What is worth doing if we cannot line the walls?
Draught proofing, secondary glazing, a chimney cover on an unused flue and heavy curtains. None of that is controlled and together it changes how a cold stone room feels more than people expect.
Will a thin insulated board still be worth fitting?
Yes, though be realistic. Going from nothing to 25 or 30mm takes most of the chill off the surface, which is what stops mould forming, and it shows on an EPC. The last 50mm buys far less than the first 25mm.
Can external wall insulation be used in the village?
Not on a stone elevation, and not in the conservation area on anything that faces the street. On a rendered rear wing away from public view it is occasionally arguable, but it is a planning conversation first.
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Get a straight answer about a solid stone wall
Thomas comes out, works out what the wall is, and tells you whether a lining is worth it or whether the money belongs somewhere else. The visit and the quote are both free.