Wall insulation in Post Green
External insulation is a render job as much as an insulation job, and inside a designated area what the frontage looks like is not entirely your decision.
The site visit is free and so is the written itemised quote. Thomas Hannen prices every job himself.
Last updated
Most houses in Post Green have a cavity that can be filled if a borescope shows it clear and dry; the older ones are solid and are lined. Post Green sits inside the Lytchett Minster Conservation Area, and that matters for walls because the one system that goes on the outside changes how the building looks. External wall insulation is a render job as well as an insulation job. Inside a designated area the appearance of what faces the road is controlled, so on many houses here the answer moves indoors or into the cavity.
The problems in Post Green are ordinary enough. A cold front room in an older house with mould in the corner. A post-war house where somebody filled the cavity years ago and one gable is showing damp. And people who have seen an insulated render on a house elsewhere and want to know whether they can have it here.
We read the wall first. One small drilled hole and a borescope shows whether there is a cavity, how wide it is and what is already in it. On a solid wall we measure the thickness and check the plaster, the reveals and the joist ends. The site visit and the written itemised quote are both free, and insulation in Post Green covers the loft too.
The work
Filling from outside, lining from inside, choosing between them
The borescope check comes first. One 12mm hole in a Post Green wall tells you the cavity width, whether mortar snots are bridging the ties, whether existing fill has slumped and whether anything in there is wet. It takes minutes and it decides everything that follows, so we will not write a specification without it.
Cavity fill. Where the cavity is clear, dry and wide enough, the wall is drilled on a pattern, filled and made good in a day. Bonded polystyrene bead flows around ties and stays put. Blown mineral wool is the older method and it works in a clean, sheltered cavity. Nothing about that changes the outside of the building except the made good holes, which is why it is the easy option in a designated area.
Internal wall insulation, IWI. On a solid wall, or a cavity that is too narrow, the lining goes on inside. Insulated plasterboard bonded to the masonry, or a batten and stud frame filled with mineral wool. PIR laminate such as Celotex or Kingspan reaches the target in the least depth; on older brick and block we would rather use a breathable board so the wall can still dry inwards, with any vapour control layer taped per BS 8000-8.
External wall insulation, EWI. Boards fixed to the masonry, a render carrier and a silicone or through coloured render over. It keeps the room size, warms the wall right through and deals with the joist ends. It also thickens every reveal, moves the sills, changes the eaves overhang and gives the house a different face, which is precisely what a conservation area is there to control.
Fill that has failed. Wool blown in decades ago settles and leaves a cold band below the eaves, read inside as black mould on the top of a bedroom wall. A wet cavity where water is crossing a bridge shows as damp patches that come and go with the weather. Both start with extraction rather than with adding more material.
The junctions. Reveals, the threshold, the floor junction, the eaves and the joist ends are where the labour goes and where trouble shows first. A cold bridge, or thermal bridge, left at a reveal collects condensation whatever the u value of the wall next to it. Reveals take a thin high performance board or aerogel, and a party wall gets a cavity barrier.
Ventilation and draughts. Both routes raise the airtightness of the house, so the moisture in it needs a way out. Trickle vents, a working extract fan and clear air bricks are part of the job, and Approved Document F sets what is expected. Sealing draughts at the same time is what turns a better u value into a room that actually feels warmer.
How it runs
Insulating the walls of a seventies house
Thomas comes out, drills a small test hole and looks into the cavity with a borescope, and costs it himself.. The written quote covers the survey and borescope check, the system and its thickness, making good around windows and doors, ventilation, and disposal.
Most houses and bungalows in Post Green have cavity walls from the seventies and early eighties, and some were filled years ago. A bungalow is drilled from the ground or a short ladder; a two storey gable needs a tower. Older solid-walled buildings in the village cannot be filled and need lining inside or insulating outside. Dust sheets go down and the holes are made good in matching mortar. A cavity found full of rubble, or already filled, is photographed and re-quoted before any drilling carries on.
Post Green is under Dorset Council, inside the Lytchett Minster Conservation Area. Cavity fill and internal lining are building control matters. External wall insulation is a planning question inside the conservation area, because appearance is controlled, and on anything listed it needs listed building consent. Where an existing wall is upgraded, regulation 23 sets what it has to reach under Part L.
Cost
Cavity, lining or outside: what changes the price
What the wall is. A clear, dry cavity on a seventies bungalow is a quick job from outside. A cavity partly filled already, or with rubble at the bottom, needs sorting first. A solid wall on an older building needs a different system entirely.
The outer leaf. Filling a cavity only works if the outside wall keeps rain out. Where pointing has washed out on the exposed side, that is repaired first.
Junctions. Window reveals, the floor junction, the eaves and any party wall are where heat escapes and condensation shows if the detail is wrong. With internal lining, sockets, skirtings and radiators come off and go back.
Access. A bungalow is drilled from the ground; a two storey house needs a tower. The work at height rules set the platform.
Ventilation. A better sealed house needs somewhere for moisture to go, so extract fans in the kitchen and bathroom are checked and sometimes added.
Ground. On this clay, old cracks in the outer leaf are checked before any fill goes in.
Ask anyone else whether they looked in the cavity with a borescope, what system and thickness they are using, and how the reveals and floor junction are being detailed.
If damp has appeared
Damp or mould appearing after insulation
Ring rather than use the form. When black spots or damp stains show on the inside of an outside wall after it was filled or lined, moisture has found a route: rain crossing the fill through a gap in the outer leaf, a cold spot at a window reveal, or steam from the room condensing behind the lining.
Keep the room warm and aired, and note which wall and after what weather. Nothing is pulled out until the first visit has found which of those it is. Post Green is about nine and a half miles from us on the Wareham side of Poole. Wall insulation work runs Monday to Friday, 8am to 6pm. If damp is spreading, ring, and if you cannot get hold of us we phone back as soon as we can.
Worth knowing
What a designated area does to an insulated render
External wall insulation is the most effective thing you can do to a solid wall, and it is the hardest thing to get agreed inside a conservation area. It is not the insulation anybody objects to.
It is the 90 or 100mm of extra thickness, which pushes the render past the original brick line, buries the sills, narrows every reveal and leaves the eaves overhang looking mean unless it is extended. On a frontage that contributes to the character of the area, that is a real change and it is treated as one.
What that usually means in practice is a split decision rather than a flat no. The elevations that face the road stay as they are, or get lined from inside, while a rear or side elevation nobody sees can take an external system. Get the council's view before you get attached to a plan, because the alternative is a house that has been insulated on three sides and a front room that is still the coldest in the building. Where the cavity will take fill, that question does not arise at all, which is the quiet advantage of the newer houses in Post Green.
Who you are dealing with
Who insulates your walls
We are based in Boscombe, which is about nine and a half miles away. Our area includes Post Green, Lytchett Minster, Upton and the Sandy Lane side, broadly BH16, under Dorset Council. You are dealing with Bournemouth Roofing & Building Ltd, registered in England and Wales, company number 15471719. Before you book a visit in Post Green, you can read our customers' Google reviews, word for word, on our reviews page.
The borescope goes in by Thomas Hannen's own hand, since it is his business and he prices each wall himself. A verified customer gave the firm 10 out of 10 on Checkatrade. The survey visit is free, and the written, itemised quote costs you nothing.
Planning at a glance
Do you need planning permission in Post Green?
Most repairs in Post Green 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 Post Green |
|---|---|
| Who decides | Dorset Council is the planning authority for Post Green. Dorset Council's heritage pages set out what it controls. |
| Conservation area | Yes: Lytchett Minster Conservation Area. Check whether your street is inside the boundary before changing anything visible. |
| Listed buildings | Yes, there are listed buildings in and around Post Green. If yours is one, work can need listed building consent. |
| Protected landscape | No National Park or National Landscape covers Post Green. |
Questions
Questions about wall insulation in Post Green
Can I have insulated render on a house in the conservation area?
Sometimes, and rarely on the elevation that faces the road. It thickens the wall and changes the frontage, so the council's view is worth having before you plan around it.
Does filling the cavity need permission here?
No, it changes nothing you can see except the made good drill holes, so it is a building control matter rather than a planning one, which is why it is the straightforward route in a designated area.
Which takes longer, a fill or an internal lining?
How long each takes is not close. A cavity fill on a normal house is a day. Internal lining runs room by room, because each room is cleared, plastered and redecorated afterwards.
Can you line just the cold front room?
Yes, and it is often the sensible order. What matters is that the return walls, the reveals and the floor junction in that room are done as well, or the cold surface simply moves.
Does insulating a wall cure condensation?
If the mould is condensation on a cold surface, warming that surface and improving the ventilation together will deal with it. If water is getting in through the wall, lining over it makes it worse.
Nearby, and next door
Wall insulation near Post Green
Nearby places we also cover for wall insulation, with straight-line distances from Post Green, and the other trades we offer in Post Green itself.
Wall insulation nearby
Our other trades in Post Green
Wall insulation guides
Damp at the bottom of a wall: what it is PIR board vs mineral wool: which insulation? Hollow-sounding wall: blown plaster or dot and dabEverything we do in Hamworthy Wall insulation, all areas Every area we cover
Free quote
Get the wall read and the constraint checked together
Thomas comes out, borescopes the cavity, says honestly what the outside can take and prices the work in writing. The visit and the quote are free.