Wall insulation in Merritown
On low ground the bottom of a wall shows the damp first, and a wall with a wet base should not be insulated until the water has been dealt with.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
Ground on this side of the parish sits low and holds water, and the first place that shows is the bottom of a wall. A wall with damp in its base is not a wall to fill, whatever the borescope says about the width of the cavity. So out here the moisture readings come before the system, every time.
Typical calls: a back room that smells of damp each autumn, a wall filled years ago that now stains along its bottom metre after heavy rain, an outbuilding or annexe nobody has ever got round to insulating.
Evidence first, then a specification. That means a borescope through one small drilled hole in a mortar joint, moisture readings taken inside and out at low level, a look at the ground and the air bricks, and a walk round every elevation. Only then does a free written itemised quote go out, with survey, system, junctions and making good listed separately.
The work
Walls on wet ground, and what can safely go in them
Before the wall at all: the ground it stands in. Raised soil levels, a path laid over the damp course, an air brick blocked up, a gulley that stopped taking water years ago. Every one of those pushes moisture into the foot of a wall. Insulate over the top and it stays there, then reappears indoors as damp and black mould. Approved Document C starts at the ground, and so does an honest wall quote.
The bottom metre. Meter readings go on inside and out down here first, because this is where the answer usually lies. Staining, salting, a skirting that has gone soft, a floor junction reading wet. Nothing goes on a wall in that condition. Fix the cause, let it dry, take the readings again.
Then into the wall, twice. A nine inch solid wall and an early brick and block cavity are indistinguishable once render is on, so we drill and scope. On low ground the scope goes in high and low on the same elevation, because a cavity can be bone dry under the eaves and sodden a metre off the ground. Gap or none, what width, clear or fouled, wet or dry, empty or filled.
Mid wall, where a cavity fill can go. Clear all the way down, dry all the way down, wide enough: that is the test. Material then goes in from outside on a drilled pattern made good in matching mortar. Bonded polystyrene bead travels into corners and holds position, which suits a weather elevation. Blown mineral wool is the older answer and still right where a wall sits sheltered. A day on a normal house.
The inside face. Internal wall insulation answers a solid wall, and answers any cavity we have declined to fill. Insulated plasterboard bonded on, or batten and stud carrying mineral wool or PIR, boarded and skimmed. Celotex and Kingspan give more per millimetre; aerogel board suits a small room. Reveals, threshold and joist ends are wrapped as standard, and the floor junction gets particular attention on this ground, because that is the one place where heat loss and moisture meet.
The outside face, and where it has to stop. External wall insulation is board on the outer face with a render carrier and a thin coat over it, wrapping the building in one pass and lifting the thermal bridge off the eaves and corners. Down at the bottom it must finish cleanly above ground level on a proper base track and bead. Take it into wet soil and the whole system wicks. Reveals, sills and rainwater pipes move outwards with it.
The head of the wall, and the air in the house. Fill that has slumped shows as a cold band up there; a wet cavity carries penetrating damp through instead. Both read off the borescope and extraction comes first. Then ventilation: trickle vents, a working extract fan, air bricks kept clear. Insulating moves the dew point and takes away the draughts, so a taped vapour control layer and breathable materials keep interstitial condensation out of the build up.
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.
Lining the inside of a wall is not development and needs no application, which Planning Portal guidance on insulation confirms, and Planning Portal guidance on external walls covers the outside face. There is no conservation area over this stretch and only a few listed entries nearby, so most of the decision here is technical rather than planning; BCP Council keeps the listed entries is where to check an address. It is notifiable work 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 cottage on the lane, a post-war house set back off it and a converted outbuilding 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 under five miles from us, so a BH23 address out here is normally 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
On low ground you deal with the water first
Flat, low lying country between the airport and the river, with surface water risk rated high; the Environment Agency flood map will show what applies to a particular address. That is not the same as saying every house floods. It means the ground stays wet for long spells, and a wall standing in wet ground behaves nothing like the same wall on a dry slope. Water rises in the outer leaf. Ground levels creep up as paths and drives get relaid. The damp course ends up bridged and nobody notices.
Order of work therefore matters more here than choice of board. Ground levels back below the damp course, air bricks cleared, gutters and gully sorted, wall left to dry. Insulate after that. Do it the other way round and you have buried a wet wall behind a lining, and the first you hear of it is mould along the skirting in the second winter. Where a wall has to be insulated before it can fully dry out, the build up goes on breathable rather than sealed, so the moisture keeps a way out.
Who you are dealing with
A local firm you can check
We cover Merritown, Hurn, the Parley Lane side and the BH23 addresses out towards the airport, 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
Merritown questions we get asked
My wall stains along the bottom. Can it still be insulated?
Not before the cause is dealt with. Ground levels, a bridged damp course or a blocked air brick have to be put right and the wall given time to dry, otherwise a lining simply conceals a wet wall.
Why do you take readings at the bottom of the wall as well as the top?
A cavity can be dry at eaves level and wet a metre above the ground. One reading in one spot is precisely how walls end up filled that ought to have been left alone.
Does external insulation go all the way down to the ground?
No. It finishes above ground level on a base track with a proper bead, so the system is never sitting in wet soil drawing water up into itself.
Are air bricks still needed once the walls are insulated?
Yes, and rather more than before. They ventilate the floor void, and blocking one to tidy up a new render is a short route to a damp floor and a smell in the room over it.
How long before a damp wall is dry enough to line?
Weeks rather than days once the cause has gone, and it varies with the wall. We take the readings again before any boarding starts instead of working to a date in a diary.
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Get the wall and the ground looked at together
Thomas comes out, takes readings high and low, checks the levels and the air bricks and prices the work in writing. The visit and the quote are free.