Wall insulation in Holt, and why nobody should quote blind
You cannot read a wall from the road out here, so one small hole and a camera settle what can be done long before anything is specified.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
There are things you can usefully check yourself before ringing anybody, and it is worth knowing in advance where each of them runs out. Render, pebbledash, paint and later extensions all hide brickwork. A house that reads Victorian from the lane may have a 1970s cavity behind the finish; a house that reads modern may be a rendered solid wall. So around Holt the survey is not a formality that precedes the quote. It is the thing the quote is made of.
What brings people to the phone is ordinary enough. A room that never quite warms up. A wall cold to the back of the hand. Black mould in the same corner every winter. Damp patches on an outside wall that come and go with the weather.
Then we drill a small hole and feed a borescope in. Out of that comes whether a cavity exists, how wide, how clean, how dry, and whether anyone has blown anything into it already. Solid walls get their thickness measured, and the plaster, the reveals and the joist ends read over. There is no charge for the visit, and none for the itemised quote written afterwards.
Before you ring anyone
Six checks you can make yourself, and where each one gives up
One. Measure a window reveal. Deep, and the wall beneath the finish may be solid, a nine inch bond or thicker. Shallow, and a cavity becomes likely. It gives up at a replacement frame, set forward in the opening, which shortens the reveal whatever lies behind it. Measure anyway: reveal depth decides whether an ordinary board fits at the frame or whether aerogel has to.
Two. Look for header bricks at a corner. Short ends every few courses point to a solid wall bonded through its thickness; stretchers all along point to a leaf with something behind it. It gives up the moment a wall is rendered, pebbledashed or painted.
Three. Sight along the mortar for a grid of plugged holes. Filled drillings roughly a metre apart mean somebody has pumped this wall already. Not the end of the matter, though, because the live question is whether that material is still even and still dry. Slumped fill leaves a cold band under the eaves and a matching line of black mould inside.
Four. Find the build date, then distrust it. Extensions, rebuilt gables and rendered frontages mean one address can honestly carry two kinds of wall on two elevations. Age is the least reliable of the six and the one people lean on hardest.
Five. Cold morning, back of the hand, every room. You are mapping which elevation is worst and where mould appears. Damp coming and going with driving rain is penetrating; damp arriving every winter in corners is condensation. The two want opposite work, and confusing them wastes money.
Six. Put your head into the loft at the eaves. On a bungalow or a low eaved house the top of the cavity is often visible from up there, along with whether fill ever reached it.
What none of the six settles. Whether anything can safely go into that wall. A 12mm hole, a borescope, and the clear width, the snots on the ties, the slumped or wet fill are all in front of you. A bridged or wet cavity gives water a path to the inner leaf, so the outer leaf gets put right first.
If the camera finds a gap. Clear, dry, wide enough: drilled on a pattern, pumped, made good in a day. Bonded polystyrene bead runs round the ties and stays put. Blown mineral wool still works in a clean, sheltered cavity. Failed fill comes out and is vacuumed away first.
If it finds no gap. Internal wall insulation, IWI, means insulated plasterboard bonded on or a batten and stud frame packed with mineral wool; PIR laminate, Celotex or Kingspan, in the shallowest build up, or a breathable make up on older brick so the wall keeps drying, vapour control taped per BS 8000-8. External wall insulation, EWI, boards under a render carrier and a render finish, keeps your floor space and settles the joist ends and the floor junction together, at the price of changing the face of the building.
Either way, the junctions and the air. Reveals, threshold, floor junction, eaves, joist ends, and a cavity barrier at a party wall. A cold bridge, or thermal bridge, at any one of them collects condensation whatever the u value beside it. Then trickle vents, extraction discharging outdoors from kitchen and bathroom, air bricks left clear, to the expectation set by Approved Document F. Airtightness without a route out is how a warm wall makes a damp one.
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.
Holt is under Dorset Council. There is no conservation area over the village, and there are thirteen listed entries in the parish, where even internal work can need listed building consent. For everything else this is a building control question rather than a planning one, and 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 rendered cottage on the green, a detached house down one of the lanes and a bungalow with a later extension on the back 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. Holt is under nine miles from us and we are past Wimborne most weeks, 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
Opening the wall is the job, not the thing before the job
Twelve millimetres. That is the whole of it. The hole goes into a mortar joint rather than a brick face, the camera follows it in, the joint is made good behind us, and the business is over in the time it takes to drink a cup of tea. Nothing about it is a preliminary. It is the only part of the survey that produces a fact, and every line of the quote afterwards is an inference drawn from what came back up that hole.
Which is also why a price arrived at without it is not a price for your wall. It is a price for an average wall, written in the hope that yours resembles one. And the answer we most often have to give is the unprofitable one: the cavity is already evenly filled and dry, the wall is done, and the same money put into the loft, the draughts or the ventilation would do more for the house than anything we could sell you. Better said in your hallway than found out two winters later.
Who you are dealing with
A local firm you can check
We cover Holt, Holt Heath, Broom Hill and the lanes towards Furzehill, 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
Holt questions we get asked
Can you tell what my wall is without drilling it?
Not reliably. Reveal depth and header bricks are worth checking and both are defeated by render, paint or a replacement frame, so a borescope through one small hole remains the only honest answer.
What does the check involve, and does it damage anything?
Twelve millimetres into a mortar joint, camera in, a look round, joint made good. Minutes rather than hours, and nothing visible left behind afterwards.
Can one house have two different kinds of wall?
Regularly. An older solid walled cottage with a cavity built extension on the back is the usual version, and the two halves want completely different treatment from each other.
How long does the actual work take?
Pumping a cavity on an ordinary house with clear access is a day. Lining goes room by room instead, and each room runs to several days once making good and redecoration are counted in.
What if the answer is that I do not need anything?
Then you get told so on the visit. A cavity already filled evenly and dry is a wall that is finished, and your money will go further somewhere else in the house.
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Have the wall opened and read before you commit
Thomas comes out, drills one hole, shows you what is in the wall and prices the work in writing. The visit and the quote are free.