Wall insulation in Lyndhurst
Most of the village has solid walls with the floor joists built into them, and that one detail decides what a lining is allowed to be.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
Close to four in ten homes in Lyndhurst were built before 1919, which means solid walls with the floor joists built into them. That one detail decides how a wall here should be insulated: put a sealed lining on the inside and the joist ends sit in cold, damp masonry with nothing moving past them, and rot takes years rather than months.
The calls are a cold front room, black mould in a corner that no amount of wiping fixes, and houses where somebody has already fitted foil faced board and the problem moved rather than went.
We look at the wall, the plaster, the floor construction and the ventilation together, because on an old building they are one system. The site visit is free and so is the written itemised quote, and where the right answer is a smaller job than you expected, that is what it will say.
The work
Solid walls, buried joist ends and the damp that follows
Where the joists go into the wall. In a pre-1919 house the floor joists sit in pockets in the external wall. They have always been slightly damp and have always dried, because the wall breathes and the room is warm on the inside face. Insulate that face and the masonry behind runs colder and wetter, and the joist end sits somewhere that never dries. The build up has to allow for that, or the floor pays for the warm room.
Vapour open rather than sealed. On an old solid wall we use a build up that lets moisture pass and dry inwards, rather than a foil faced board that stops it dead. BS 5250 is the code for managing moisture in a building and it is the reason interstitial condensation is designed out rather than hoped away. Where a foil faced PIR is right, on a later wall, it gets a properly sealed vapour control layer and the joist ends get ventilated.
Internal wall insulation, done properly. Insulated plasterboard on a continuous adhesive bed, or PIR such as Celotex or Kingspan between battens or a stud, taped and skimmed to BS 8000-8. Coldest rooms first. Reveals returned with a thin board or aerogel, the threshold and the floor junction detailed, and the lining run a short way onto the party wall so the temperature drop happens inside the insulation.
External wall insulation. Boards and a fresh render over a render carrier. EWI gives the best U value on a solid wall and cures the cold bridge at every floor junction and joist end at once, which is exactly the problem above. In the conservation area it is a planning application and on the frontages here it is a hard case to win, but on a rear elevation it is worth asking about.
Cavity walls on the later houses. One hole in a mortar joint and a borescope gives the cavity width, whether it is clear and dry, whether the ties are bridged and whether a failed or slumped fill is in there. A sound cavity takes bonded bead or blown mineral wool from outside. We do not offer a guarantee scheme of our own; a cavity fill is normally installed under an independent one, so ask who is drilling which scheme covers it.
What we would talk you out of. A sealed lining on a solid wall with buried joist ends and no ventilation added. It raises the EPC, it warms the room for a winter, and it quietly makes the fabric worse. If the money will only stretch to one thing, draughtproofing and the loft have a shorter payback and no risk attached.
Ventilation. A tighter house with the same number of showers needs somewhere for the moisture to go: trickle vents, a working extract fan in the kitchen and bathroom, and air bricks kept clear rather than boarded over. Approved Document F sets what the ventilation has to reach, and on an old house it is the half of the job people skip.
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, not the district, and the National Park sets out its heritage position for the Lyndhurst conservation area that covers the village. Inside it, cladding or external wall insulation is an application; lining a wall on the inside is not development at all, which the guidance on insulation confirms. There are about thirty listed entries in the village, and on a listed building consent is needed for internal work as well. regulation 23 brings a whole wall up to the Part L standard once more than half of it is renovated, and building control is the district rather than the Park.
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 Victorian terrace on the high street, a detached house set back in trees and a flat above a shop are three different jobs. 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 a floor near an outside wall has started to feel soft, say so when you ring, because that changes the order we look at things in. The phone is answered 24 hours for emergencies; scheduled work runs Monday to Friday, 8am to 6pm.
Worth knowing
Why a sealed lining rots an old floor
It is worth understanding the mechanism, because it is the single most common way an old house is damaged by good intentions. The wall is solid, so it gets wet in driving rain and dries out again from both faces. The inside face has always been the warm one, which is where most of that drying happens, and the joist ends sit in the wall inside that same drying zone.
Put an insulated lining on the inside and you move the dew point. The masonry behind the board now runs colder and stays wetter for longer, and the drying path inwards is gone. The joist ends, which used to sit in a wall damp in January and dry by April, now sit in one that is damp all year. Nothing shows for a long time, and then a floorboard gives near the wall.
The answer is not to leave the house cold. It is to use a vapour open build up that still lets the wall dry inwards, to leave the joist ends ventilated where the floor construction allows, and to add the ventilation the tighter house needs. Where none of that can be done properly, external insulation on a rear elevation is the better route, and we will say so.
Who you are dealing with
A local firm you can check
We cover Lyndhurst, Emery Down, Bank and the roads out towards Ashurst, broadly SO43, 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
Lyndhurst questions we get asked
Is insulated plasterboard safe on a solid Victorian wall?
Only with the right build up. A vapour open system that lets the wall dry inwards is fine. A foil faced board with no thought given to the joist ends is where the trouble starts.
What does breathable actually mean on a wall?
That moisture can pass through the materials and evaporate away rather than being trapped behind them. It does not mean draughty, and it does not mean cold. It means the wall can dry.
Our floor is bouncy near the outside wall. Is that related?
It can be. Joist ends built into a damp solid wall are the classic place for slow decay, and a sealed lining fitted over them makes it more likely. It is worth looking before you insulate, not after.
Can we insulate the outside instead in the conservation area?
On a frontage it needs an application and is a hard case here. On a rear elevation out of public view it is a reasonable question to ask, and it is the warmer answer if it is allowed.
How long does one room take?
Days rather than weeks, with the making good and decorating following it. We would rather do two rooms properly than four in a rush.
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Get an old wall looked at before it is lined
Thomas comes out, looks at the wall, the floor and the ventilation together, then prices the work in writing. The visit and the quote are free.