Night Owl

Thank you Nick, i wouldn't have thought about it that way as I've been more focussed on maintaining the structural integrity of the installation. From the way you describe it, sounds like it's pretty common practice to 'chop' timbers before installation to address this type of issue? I'm surprised Velux don't pass this onto their approved installers as my window was actually fitted by one. Building control never mentioned it either when they looked at it.

Thanks for the replies. Personally I can't see what effect drilling a couple of small holes would have on the overall structure of the roof. For info, it is approx. 70 years old, made up of concrete tiles, 1x1 lats, bitumen felt, 4x2 rafters plus the 2x2 batons I've recently added to increase depth for insulation.

Thanks Wil, hopefully someone will be along soon to enlighten us. In the meantime, if I do find something I will post it here.

Anyone have any thoughts on the above?

Hello, I recently had a Velux window installed in my roofspace which will be used as an en-suite for the upstairs bedroom. I will be insulating between the rafters leaving a 50mm gap for ventilation between the roof felt and insulation. There are two areas (to the left and rightof the window) that will be effectively sealed off (due to double trimmers being fitted) from the ventilation path once plasterboard has been fitted. Would it be acceptable to drill these trimmers top and bottom to allow some airflow through the void? If it is, what would be the best quantity / size / location for these holes? Thanks.

Thanks again for the reply. Whilst I am lucky to have a blank canvas for my heating choice, I don't unfortunately have a blank cheque! I'd love to have a ground source heat pump but don't have the space or money for a bore hole system. I have however already installed the wood burner (multifuel actually) and am slowly building up a decent supply of logs for future use. Interesting info on air source heat pumps which I need to look into in greater depth. Interesting link you provided to see how heat pump installations are faring. Sounds like there is a lot to consider when designing a system for maximum efficiency. Finding a good installer who knows what they are doing could prove challenging in my area - only one listed in the link who also do gas and oil so not a dedicated renewables company. I agree that the price of oil is likely to go only up in the future as less and less gets extracted from the ground (if you believe this) but you can at least buy it when the price is cheaper during the summer months and store it for winter - something you can't do with electricity. I've never lived in a house where the heating is constantly on. I'm used to only having it on when needed which I know can be quite inefficient however my bills have always been reasonably low. As I'm getting older now and at home full time it could well make sense to have a system running all the time at a lower temperature for efficiency and overall comfort. Would be nice to not need an oil or gas tank freeing up some space. Lots to consider and research!

Thanks for your comments IGP. Interesting thoughts on insulation. My floors are unfortunately solid concrete with a bitumen DPM that has worked to a point but not completely. I'm planning on digging up some of the floors in the house to get some insulation in but finding someone willing to do it is proving a little difficult. I am lucky to have a blank canvas for the heating system that goes in, every option available bar mains gas. I have looked into heat pumps but always thought they only work well in a well insulated leak free house. I'm also nervous of being held to ransom by the electricity companies. Don't have the appetite for solar panels and battery storeage yet so may opt for oil heating. Has anyone ever heard of an oil heating system working with oversized radiators to run at a cooler flow temperature in a similar way heat pumps do?

No such thing as a stupid question! My aim is to improve the overall comfort within the bungalow without compromising the fabric of the building. I want the property to feel warmer, use a little less energy and have no future issues with damp (as a result of my work).

Thanks for the reply and advice on how you would tackle this situation. I have decided not to add anything to the exterior brickwork which is in reasonable condition and quite sheltered from the elements. I'm slowly going round sealing up areas where air can escape. I am realistic in thinking I won't plug every gap but will at least be able to make a decent improvement. Interesting that you would get rid of the cavity insulation and replace with beads. I understand that the beads are probably the best option for my situation and will look to getting a quote for this. Is it vital that the cavity is filled if adding IWI to avoid condensation issues? I presume the idea is that it will help keep the inner wall a little warmer?

Looking for thoughts on how others would tackle improving the insulation on my late 1950's dormer bungalow in the East Midlands. Wall make up is - Outer face 110mm red brick Inner wall 110mm red brick Cavity fill insulation is a white cotton wool material but lighter. Due to issues with damp I have had to clean out the lower part of the cavity walls above (and sometimes below) the slate DPC due to being full of material waste from the build. The cavities are now clear but as a result I have large voids around the lower part of the walls where the insulation has been lost. As I have removed all internal plaster from the walls I am looking to improve the insulation in and/or on the walls. Don't want to go EWI as I like how the bungalow looks as it is and it would be quite expensive. I'd like to batten out the internal walls that form the outside walls and add insulation and an Intello plus vapour barrier, then board and skim however I am concernedabout potential condensation issues going this route. Should I get the CWI removed, replaced or try and top it up? There is space in the rooms to add around 50mm extra IWI without looking odd. I have used sheep wool to insulate the loft which I like as a product although very expensive. 50mm in the walls won't make a lot of difference so would be interested to know what others would install. Thanks.

Haven't found a concrete company yet interested in delivering, probably due to the small amount. Quite a few don't carry pumping equipment too so that would be an extra hire cost. Looks like it might have to be done manually Anyone got a good formula / mix recommendation for waterproof concrete?

Hi, no not that I can see however the door that accesses the room was on an outside wall.

Looking for a few pointers in regards to the old boiler room in my house (1950's bungalow) which would have been originally solid fuel. It is approx. 3.28m2 and was constructed partally below ground for some reason but has long been removed. The floor level in the cellar is about 800mm below (slate) DPC and usually has between 6 and 12 inches of water in it during the winter months. Picture above was taken today where it has all but finally dried out. I want to bring the floor level up in this room to match the rest of the house, so approx. 800mm needed. My thought was to get a concrete company in to pour waterproof concrete to approx 300mm below dpc (1.64m3). Install DPM, insulation 200mm, 50mm concrete then screed to existing floor level. Can anyone see any issues with this approach or suggest a better (easier) way? Would also be interested to know why it was built below ground level. Thanks.

Thanks for the info Gus, makes sense. Just for clarity, when I posted earlier that all of the lintels at my property are the same, I didn't mean they had all been cast incorrectly. Just the one rogue one as far as I can tell! There are a couple of doorway formed from brick arches which look quite impressive from an old school builders point of view. I won't post any pictures of them as it could lead this thread down a whole new debate. Thanks again for all the input.

Thanks for the responses. I think the Lintel failed as it had been cast badly, probably 70 years ago. Only two bars in it and both next to eack other. All of the lintels in the property are of this type and set in brick that wouldn't meet current best practice. In the end I set it on a mortar bed and packed out above with slate before pointing up. Very little weight, bungalow non load bearing wall. All of the remaining lintels look solid with no signs of any movement. S.E didn't raise any concerns.

Hello all, after some advice on a concrete lintel replacement. Single skin non loadbearing wall had a cracked concrete lintel above it. Have removed old one and looking for best practice on installing new one. Have installed it smooth side down. Do I bed it on mortar or use slate under the lintel? Thanks

Hello again. Have now had the window replaced on the Dormer so ready to start insulating in that area. Unfortunately trickle vents were added in a location that reduces the thickness of ceiling I can have so made the decision to remove them (Left one already done). Will seal them up with foam or silicon. I intend to install whole house ventilation later so hopefully won't be an issue. Still confused as to the best method for insulating the dormer roof and cheeks. Currently the roof has two layers of green mineral felt torched onto the wooden boards. The side cheeks have a covering of lead onto the wooden boards. As mentioned in the original post, I have 100mm in the roof joists and 50mm in the cheek batons. The maximum I could probably goto now on the ceiling is 170mm including thickness of plasterboard & skim. The maximum on the cheeks is 80mm including plasterboard & skim. Still keen to use sheep wool if I can and would look at putting 150mm in the ceiling (leaving a 20mm air gap) and 50-60mm in the cheeks leaving a 20-30mm air gap. Although they say wool doesn't need a vapour barrier I would look to install an Intello membrane over it to help reduce moisture reacing the timber. I've also considered using phenolic insulating boards as it is supposed to have the best insulating properties where space is limited. My questions are - Do I really need to be leaving an air gap with either method if I install the Intello membrane? Could a combination of both materials be used i.e wool between joists/batons, the cover with phenolic plasterboard? Cost not really an issue for this part of my refurb.

Thanks for the replies. I hadn't considered external insulation but agree it would be the best solution. Unfortunately it will probably be a bit outside my budget and bryond my skillset to make a decent job of it. Will definately be looking to make use of the pro clima intello membrane. Hadn't heard of it before but sounds like a very good idea. One of the reasons sheep wool interested me apart from being a natural product was it's fire retardent properties. Hemp sounds a great material but a bit lacking in this department. There are now companies claiming to sell sheep wool that doesn't have an issue with moth infestation. See link - https://www.sheepwoolinsulation.com/about/ionic-protect/ No idea if this 'ionic' system works to solve the problem with moths. Would fibre sounds interesting too, gain I wasn't aware of the product. So many products and ways to insulate a property these days makes it really confusing. Utimately, I guess any insulation I install will be better than none as is the current situation - providing I don't introduce a condensation / damp problem. That is the key. Looks like I've got more research to do but appreciate listening to what others have found to work for them.

Interested to know how forum members would set about insulating the dormer of my 3 bed late 1950's bungalow? Timber construction as in the picture below with a mineral felt roof covering. I've only got approx. 100mm deep joists on the roof part and 50mm on the cheeks. The rest of the room sits in the roof space (not insulated at present but have probably sheeps wool installed between joists) and is of old 'concrete' block construction. My thoughts were to use sheeps wool throughout but not sure if vapour barriers / air gaps are needed? Also planning to add batons to 'external' walls of dormer room and add sheeps wool there. I like sheeps wool due to it's natural properties and breathability. How would you set about this job? Thanks.

Moved onto the bay window section today. Floor sounded rather hollow in the front part of the bay and started to crumble when hit with a hammer. Totally gone, so dug it all out. The 'cavity' between the main floor slab and inner wall of the bay had been deliberately filled with rubble. A thin slab had been laid over the top. No damp proofing on this part of the floor. The main slab has bitumen however there was some damp between this and the wooden floor - possibly due to a water leak last year. Any suggestions for damp proofing this area and building up the new part of the floor?

Left this wall for a few weeks however it doesn't appear to be drying out as I'd hoped - the cold weather not helping. Decided to continue cleaning out the cavity, it was pretty blocked up! All cleaned up as best I can now for this section. Will brick up the opening now and leave to see if it makes any difference. Should I replace the wall insulation removed behind the bricks I took out? It was the white wooly type stuff that had been installed. Will not replacing it cause a cold spot at the lower section of the wall or will no insulation mean it will be better ventilated?

Hi crispy_wafer, did you ever get BI's take on your notching of the wallplate? Reason I'm asking is that I will need to do something similar to allow some conduit for electrical cables I will be chasing into my walls. Basically need to chase brickwork deep enough to allow conduit to sit in, however it then hits the wooden wallplate at the top of the wall. Ceiling plasterboard is level with base of wallplate.

Hi, thanks for the replies. The property has been in this state for about 8 months now. Had windows open throughout the house every day over the warmer months, but only got the plaster removed over the last three. Lots of draughts throughout due to old windows so there is airflow. May set up a fan in this room to see if it helps. kandgmitchell, the dpc (slate) on the inner leaf is practically level with the bitumen on the floor slab, directly below the brick I've removed. Water could well be tracking under the slab to the edges. Plaster was installed below the dpc/bitumen on the walls which I'm in the process of removing and cleaning out the wall/floor channel. Started stripping out the living room today which has exactly the same problem. I know there is water under the property as I have an old boiler room in a very small 'half' cellar that has filled up by about 3 inches of water over recent months during all the rain. I plan to dry this out later in the year, tank it and fill it in up to floor level. Where the water is coming from is unclear, I know the water table is quite high but to my knowledge, the property has never flooded.

It's been pretty dry for the last three or four days. Not much difference noted inside but suspect it is too cold to properly start drying out. Looked outside today and it is interesting to note that the ground has dried up apart from an inch or so around the base of the wall. I presume ground water must still be finding a way up the wall from the foundations below ground. Been looking at ACO drains and French drains as a possible solution to help with the situation possibly connecting up to a new soakaway. The whole front of the house is concrete though so will be a pain to excavate.

Inside the cavity looking down from DPC (i.e below the slate) it seems to be pretty clear. Although there was a great lump of brick in there Above the slate line a different story. Its only a 50mm cavity and the slate sticks out into the cavity from inner and outer leaves leaving just enough room to fit my fingers through - this is why the fallen mortar hasn't dropped right to the foundations and has built up on the slate Completely clogged above the DPC. I can't put a dehumidifier in the room to try and eliminate the condensation theory as there are so many gaps around windows and only a partial ceiling at the moment. Any input most welcome.