Wall insulation in Woodlands, older cavities inside
A cavity from the fifties or early sixties is not the same animal as a modern one, and what the camera finds in it decides everything.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
Plenty of houses here have a cavity, but a lot of those cavities date from the late 1950s and early 1960s, and that is the awkward end of the range. They are often narrower than people expect, they frequently have mortar bridging the gap, and many were built before cavity trays over the openings were standard. So the question is never simply whether there is a cavity.
The calls we get are a chilly bungalow with a lot of external wall for the size of it, a damp patch on an inside face after heavy rain, and houses where fill went in years ago and nobody knows what kind.
The free site visit settles it. One drilled hole in a mortar joint, a borescope through, and we can see the width, the debris at the base, the state of the wall ties and whether anything is in there already. Then a written itemised quote with the survey, the material, the drilling and making good, the reveals, the ventilation and the making good all priced separately.
The work
What a fifty year old cavity actually looks like inside
The camera, and what it finds. Mortar snots on the ties bridging the gap. Debris and dropped mortar sitting in the bottom of the cavity. A gap of 40 or 50mm where the plans said more. Ties that have corroded and expanded, sometimes enough to lift the outer leaf and start cracking the joints. None of that is visible from either side of the wall.
Cavity trays, or the lack of them. Over every window, door and abutment there should be a sloped tray taking water back out to weep holes. On a lot of houses of this age there is nothing. Fill a wall with no trays and any water crossing the cavity has an unbroken path to the inner leaf, which is how a dry house becomes a damp one.
What we fill, and with what. Where the cavity is clear, dry and wide enough, bonded bead is the safer material on an older brick and block wall: it flows past obstructions, gets into a narrow gap and does not slump later. Blown mineral wool suits a wide, clean, sheltered cavity. Drilled from outside on a grid, filled, holes pointed to match, a day for most houses. Part L sets what the finished wall should reach.
What we refuse. A wet cavity, one bridged with mortar, one full of rubble, one under about 50mm, or a wall with no trays. On those the fill saves a little heat loss and buys a large risk of penetrating damp, and we would rather lose the job than do it.
Fill that has already failed. Mineral wool blown in decades ago can settle and leave the top metre of the wall empty, which shows up as a cold band under the eaves. Bead can escape through a hole in the inner leaf. Both come out through drilled holes, the wall is dried, and we give an honest view on whether it goes back.
Solid walls and single skin. The older cottages and the odd converted outbuilding have nothing to fill and take internal wall insulation or external wall insulation instead. IWI is insulated plasterboard or PIR such as Celotex or Kingspan on a batten or stud frame with taped joints and a continuous vapour control layer, or wood fibre and lime where the wall must stay breathable so the dew point sits somewhere that can dry.
Reveals and junctions. Filling a cavity leaves the reveals, the threshold, the floor junction, the eaves and the joist ends as cold bridges, and those strips are where condensation and black mould appear. Shallow reveals take an aerogel laminate. Houses of this period rarely have anything at the reveal at all.
Ventilation. Trickle vents, working extract fans and air bricks kept clear, to the rates in Approved Document F. Better airtightness with no ventilation just moves the problem.
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.
The New Forest National Park Authority is the planning authority here rather than the district council, and this part of the parish sits in the Forest North East conservation area, so anything that changes the outside face of a wall is an application; the interactive property map shows what covers your address. A cavity fill and internal work are not development, per the Planning Portal's insulation guidance, and regulation 23 brings building control in once more than half a wall is renovated.
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 wide fronted bungalow, a 1950s detached house with narrow cavities and an older cottage with solid walls are three different jobs, and the bungalow has the most wall of the three. 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. If the damp shows as a band high on the wall rather than low down, mention it, because that usually means fill that has slumped rather than anything coming up from the ground. The phone is answered 24 hours for emergencies; scheduled work runs Monday to Friday, 8am to 6pm.
Local
Cavities built before the rules caught up
The bulk of the housing round here belongs to the late 1950s and early 1960s, and that is a specific and slightly awkward vintage for wall insulation. Cavities existed by then, but the details that make them work were not yet routine. Trays over the openings were often left out. Workmanship on keeping the gap clear varied enormously. Wall ties were mild steel with a coating that has had sixty years to fail.
None of that means the walls cannot be insulated. It means the survey is the important part, and the answer differs house to house on the same road. Two identical looking bungalows built by the same firm in the same year can come back with one clean 60mm cavity and one half full of dropped mortar with no tray over the front door. There is no way to know which is which from the outside.
The other local point is shape. This is bungalow and wide fronted detached country, so the external wall area per room is high compared with a two storey house, which means the wall is a bigger share of your heat loss and a successful fill is worth more here than the same fill on a town terrace. Where the cavity will not take one, the money is better spent on the loft and the draughts than on lining every room.
Who you are dealing with
A local firm you can check
We cover Woodlands, Netley Marsh, Ashurst, Bartley and the lanes towards Totton, broadly SO40, under the New Forest National Park Authority. 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
Woodlands questions we get asked
My house is from the fifties. Can the cavity be filled?
Often, but not always. Cavities of that age are narrower, more likely to be bridged with mortar and less likely to have trays over the openings, so the camera decides rather than the date.
What are wall ties and why do they get mentioned?
They are the metal ties holding the two leaves together. Older ones corrode and swell, which can lift the outer leaf and open the joints, and that is a repair before it is an insulation job.
Why would a damp patch appear high up on a wall?
Usually because an old fill has settled and left the top of the cavity empty, or because there is no tray over a window. Neither is rising damp and neither is fixed by a dehumidifier.
Does a bungalow have more wall to deal with?
Not harder, but there is more external wall for the rooms inside, so there is more of it to do and more to gain. It also means no scaffold, which keeps the access simple.
Can you take old cavity insulation out?
Yes. It is extracted through drilled holes from outside, the cavity is cleaned, the wall is dried and then you get a straight answer about whether it should be refilled.
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See inside the cavity before deciding
Thomas comes out, puts a camera in the wall, checks the ties and the trays and prices it in writing. The visit and the quote are free.