Wall insulation in Downton
On the old streets the windows are staying where they are, which makes the reveal around each one the part of the job that decides whether it works.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
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The older houses in Downton have solid walls, so they are lined inside, not filled, while newer ones may have a cavity a borescope can check. On a house with thick old walls and small openings, insulating the middle of the wall is the easy bit. The window reveals are what decide whether you end up with a warm dry room or a warm room with black mould round every frame. In a village where the frontages are protected and the windows are not moving, that detail is the job.
The typical problems on these streets are a cold front room on a terrace, mould round a window in a bedroom, and houses where somebody lined a wall years ago and stopped at the plaster line.
The free site visit covers the wall and the openings together. Reveal depths measured at every window, a borescope through one drilled hole where a cavity is possible, moisture readings at the skirting, and a look at the ground level outside. The written itemised quote then prices the survey, the system and its thickness, each reveal, the ventilation and the making good separately. Insulation in Downton covers the loft and floors.
The work
Walls, openings and the strip in between
Establishing the wall comes first. On a Downton house, reveal depth and brick bond give the first opinion; the borescope gives the fact. Cavity or solid, how wide, clear or bridged with mortar, dry or a wet cavity, empty or filled and slumped. On the older terraces most walls turn out to be nine inch brick with nothing in them at all.
Cavity fill where there is a cavity. Bonded bead for a narrow, obstructed or weather facing wall; blown mineral wool for a wide, clean, sheltered one. Drilled from outside, blown in, holes pointed to match. One day, and the shortest payback of anything here, with Part L setting what the finished wall should reach.
Solid walls. Nothing to fill, so it is internal wall insulation or external wall insulation. On a protected frontage EWI is usually out, which puts the work inside, and inside is where the reveals start to matter.
The reveal problem. Put 60 or 100mm of lining on the face of a Downton wall and stop at the window, and you have made the reveal the coldest strip in the room. It is also the wettest, because that is where the warm damp air meets it. Yet a lot of these openings have only 30 or 40mm of reveal to play with before you are covering the frame.
How we solve it. A thin high performance board, or an aerogel laminate where there is almost nothing to give, carried right up to the frame and sealed to it. Where the frame is being replaced anyway it can be brought forward instead, which is much the better answer if the timing works. The head of the opening and the sill get the same treatment, because a cold lintel behaves exactly like a cold reveal.
The other junctions. The threshold, the floor junction, the eaves and the joist ends built into a Downton wall are all cold bridge points. The lining runs down behind the skirting and returns onto the party wall, and joist ends in a solid wall get a detail that keeps air round them rather than sealing them in.
Build ups. Insulated plasterboard or PIR such as Celotex or Kingspan on a batten or stud frame with taped joints and a continuous vapour control layer on sound modern Downton walls. Wood fibre in lime on old solid ones, so the dew point lands somewhere that can dry and interstitial condensation has no chance to build. External systems use a mesh basecoat and a render carrier with a finish chosen for the street.
Ventilation, and failures. Trickle vents, extract fans that work, air bricks left clear, to Approved Document F. We also strip linings that are cracking and damp behind, and extract fill that has failed, before anything new goes on.
How it runs
Cavity fill or internal lining, and how each one runs
The first question is what kind of wall you have, and Thomas answers it on site. A cavity wall gets one small hole drilled and a borescope pushed in to look, and a solid wall gets checked for damp while he asks how you use each room.
The quote prices the survey, the insulation system and how thick it is, reworking window and door reveals, any ventilation needed, and the waste. If a cavity fill is right, a registered installer puts it in under a CIGA certificate.
Downton has both kinds. The pre-1900 cottages are solid brick and cannot be filled, so they are lined inside with insulated plasterboard or a breathable wood fibre board, room by room, with sockets, skirtings and reveals moved and made good. Post-war houses usually have a cavity, which is filled from outside off a ladder or tower. Rooms are sheeted, dust is kept down and waste leaves with us. If a cavity turns out to be full of rubble, we photograph it, price the extra and wait for your answer.
Wiltshire Council is the planning authority. Anything that changes the outside face of a wall may need an application, especially within a conservation area, if your address is in one, and on a listed building consent covers internal work too under section 7 of the 1990 Act. Lining a wall from inside is not development, as the Planning Portal's insulation guidance explains, though regulation 23 means building control is involved if you renovate more than half of a wall.
Cost
What the walls of your house mean for the cost
Cavity or solid sets the cost. A clean, dry cavity takes a day to fill from outside. A solid brick wall has no cavity to fill, so it is lined inside or wrapped outside, and that is a much bigger job. Until a borescope has been in, nobody can tell you which you are paying for.
Windows, doors and floors. Heat leaks, and condensation forms, at the reveals round windows and doors, where the wall meets the floor, at the eaves and along any party wall. Detailing those properly is fiddly, and it takes up most of the time.
What comes off the wall. Lining a room means radiators, sockets, skirtings and sometimes kitchen units come off, and all go back afterwards.
Getting to it. Filling a cavity is done from outside, a bungalow off a tower and a tall gable from a scaffold platform, under the work at height rules. Internal lining is done indoors, so it is your rooms that are disturbed.
The right board. An old solid wall needs something that lets moisture move through it, such as wood fibre finished in lime plaster. A foil-backed board on that wall can trap damp behind it.
Ask other firms whether they have actually looked into the cavity, which system and thickness they propose, and how they will finish the reveals.
If damp has appeared
Damp or mould after wall insulation went in
Damp or black mould turning up on an outside wall after it was filled or lined is worth a phone call rather than the form. Wipe the mould off with a mild solution and keep the room aired.
The cause is usually rain getting across the insulation in the cavity, or warm indoor air hitting a cold spot at a junction. We look at the wall from both sides on the first visit before anything is pulled out, because the fix depends on which it is. Mould round a window points to the reveal, and that can often be put right on its own. Our planned hours are Monday to Friday, 8am to 6pm. Ring for anything urgent, and a missed call gets a ring back as soon as we are free.
Local
Old openings in protected frontages
Downton parish has over a hundred listed entries and a conservation area over the older streets, and the practical effect on wall insulation is not the one people expect. It is not that you cannot insulate. It is that the windows are staying exactly where they are, in openings that were never designed to have anything added around them.
That turns the reveal into the whole engineering problem. On a modern house you insulate the wall and take a normal board round into the reveal and it is done. On these houses there are often only a few centimetres between the plaster face and the frame, so a standard board would cover the window. The answer is a much thinner, much better performing material in that strip, sealed hard to the frame, and it is worth paying properly for because it is where the condensation and the mould land.
It also changes the sequence. If the windows are due for replacement, do them and the wall together and bring the frames forward into the new lining. If they have just been done, the reveal is what you have and the specification has to work with it. Either way we measure every opening on the survey rather than quoting a wall area, because on these houses that is where the real cost of the job sits.
Who you are dealing with
A named firm for wall insulation in Downton
Downton is 18.4 miles from Boscombe, where our base is. We insulate walls here and in Charlton All Saints, Redlynch and the villages along the Avon towards Salisbury, where Wiltshire Council is the planning and building control authority.
You deal with Bournemouth Roofing & Building Ltd, a company registered in England and Wales, number 15471719. Its owner, Thomas Hannen, surveys the walls and prices the job himself. There is a verified 10 out of 10 from a customer on Checkatrade. The survey visit is free, as is the written quote with each item listed. Before you book a visit in Downton, you can read our customers' Google reviews, word for word, on our reviews page.
Planning at a glance
Do you need planning permission in Downton?
Most repairs in Downton need no application at all. What decides whether a change to the outside of your house does is who the council is, whether a conservation area or a listing applies, and whether the place sits in a protected landscape.
| Question | In Downton |
|---|---|
| Who decides | Wiltshire Council is the planning authority for Downton. |
| Conservation area | Yes: Downton Conservation Area. It covers part of Downton, so check whether your street is inside it. |
| Listed buildings | Yes, there are listed buildings in and around Downton. If yours is one, work can need listed building consent. |
| Protected landscape | No National Park or National Landscape covers Downton. |
Questions
Questions about wall insulation in Downton
My reveals are too shallow for insulation. What now?
A thin high performance board or an aerogel laminate goes in that strip instead of a standard board. It performs like something several times thicker and keeps the frame visible.
Should I replace the windows before or after insulating?
Before, or at the same time, if they are due. The frames can be brought forward into the new lining, which is much the best solution to a shallow reveal.
Why is the mould only around my windows?
Because the reveal is colder than the wall around it, so it is the first surface warm damp air reaches its dew point against. Insulating the reveal and improving the ventilation deals with it.
Can a listed house on the main street be insulated inside?
Often, with consent and the right build up. A breathable, reversible lining in wood fibre and lime is a far easier case to make than rigid foam screwed through historic plaster.
How much does the room shrink?
About 60 to 100mm off each wall that gets lined, depending on thickness. In a small terraced room that is noticeable, which is another reason to do the coldest walls rather than all of them.
Nearby, and next door
Wall insulation near Downton
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Free quote
Have the openings measured, not just the wall
Thomas comes out, measures every reveal, works out what the wall is and prices it in writing. The visit and the quote are free.