MattMiller

So External wall insulation would mean redoing the lower half of the roof and as it is a stone built property, I guess it would not do any good for the stone work. The cement render certainly doesn't. There is next to no overhang of the roof to the walls. Ive put in some interior pictures. the main hall way is north facing and bloody cold. 80mm air gap behind the plaster and no insulation. not lathing as the internal walls have been done in the past 20 years. added in bedrooms as there is not a huge space for internal wall to external wall . there are portions which have old glass fibre behind the plaster, but not everywhere. @Redbeard I have done this type of install on an old cottage before with my cousin, Internally I would love too but the hall way would encroach too much. the rest of the building could potentially be OK as there is large space to do so, The bedrooms again I think it would encroach too much, but a suggestion on what thickness would be helpful as I am not an expert in this.

HI All, I am having some bother finding a reputable installer of insulation that wont just offer up any old solution... I have a limestone built house. which has been cement rendered and painted. I know not good. Plan is to remove it long term. Right now I'm trying to insulate the house, Now I know a fibreboard method and lime plaster will work. but disrupting the house for many many weeks. What the current interior build is made up of a non foil backer 12mm plasterboard and plaster onto a wooden framework that sits about 80mm from the main house wall. Roof is a cold system so there is airflow behind the plaster walls which makes them very cold. Roof has 400mm wool insulation Solutions I have been offered are Kingspan bonded to plasterboard and placed on the existing wooden frome work (removal of old plaster) Blown Bead insulation between the existing plasterboard and limestone wall Can any one advise as, mostly the companies that are accredited insulation installers want to build a frame on existing walls with 30mm gap and 60mm insulation and plaster. This would be fine but intrusive on the room sizes.. Can anyone advise or provide any information as I am trying to get grants to do the work and without quotes and correctly done I'm lost

@AliG hi and thank you for your input , are you scottish based? So the 30,000+ quote for windows are all fixed other than a sliding door changed for French. As a point of exit. The info on u values is great also. I've been looking at lifting the bottom row of tiles and moving the velux window up the roof to be able to get more insulation in there. Only I've had so many roofers out and not one has been able to tell me how to do it. The closest I've come is a block who suggested removing a row of tiles but he honestly from his point doesn't know the right way about doing it all. Certainly can replace the flat roof with a 4 layer felt system for me. Seems odd there is so infrequent I'm able to get people out that know what the answer is. They can all replace the roof to make water tight though but not solve the insulation point. If your in the business and in Scotland give me a PM... I've had one Roofer come with options to pitch roof, although I'm still not too convinced he knows how to solve the insulation of the roof. Seems like it's lost knowledge or few actually know and just throw in glass wool or the like. Has anyone used open cell spray foam as Opposed to closed cell? It's like getting our biomass boiler fixed by someone reputable. I'm resulting to being trained myself to service Eta boilers... thankfully the UK distributer is willing to help and train me up.

Can you point me to the Scottish regs on this. I'm actually wondering if I can lower the roof when I take the osb off to accommodate for more insulation and warm roof setup. This is busting my head. That and I'm struggling to did a builder to come see if a pitched roof is doable.

@Iceverge thanks for the link. Interesting comment on the page “In a compact roof assembly featuring Majrex®200, and using a high quality rigid insulation with a lambda value of < 0.026 W/mK, you may only need as little as 60 mm of insulation above the roof deck to ensure a safe construction. We see this as a safe solution, and are happy to write a warranty for our product, and to perform condensation risk calculations for our customers.” In essence this is what I've been looking for. I have contacted a building contractor to get them out for costing a pitch roof. Slowly seeing the benifit. Would like to know how the condensation calculations work. Ie first principles. Such a difficult place to be as we have a leaking roof. Want to do the best job, but stuffed for the cost of repair. Does annoy me when people cover up mistakes like this as I just couldn't bring myself to sell a house with this problem.

I think I'm understanding now. Thank you. No matter what we do here with such a small insulation is going to be poor. Absolute out the box thinking here. If I place the osb to the underside of the structural beams... damp membrane over and in-between completely sealed off. insulate between rafter and 50mm on top. 18mm ply and Firestone rubber. Leave the gap below the rafter essentialy not Insulated but make a sandwich of insulation in the roof as such... Whats the thoughts here. Stupid idea?

Ok so I have had a look at this and I'm not 100% what I'm reading. What I have tried to put in from unknown plasterboard there is about 200mm air before the structural timbers and osb on top. Max osb I could build a warm roof with would be 50mm as the build would be Plasterboard , structural rafters ,18mm osb, membrane, 50mm PIR boars insulation, 12mm osb3 and then rubber. Giving me about 10mm clearance from the tiles on the main roof. In theory I could reduce tge slope of the last tiles so as to Rais the bottom edge or would cutting them be an option? Would rather not.... If I some how raised them then I could get 100mm insulation in there....

@Iceverge thank you for this. Will look at those sites. When you say combination of warm and between the beams. Do you mean with an airgap below the osb or direct onto osb when you have a thin warm roof? How do you know how much is too much to avoid a dampness with the dew point. Are there calculations for this or experiences you can relate to? Thanks fella

@Radian thanks for the nice remarks on the house, dream home and went all in on securing this one, that said the alteration costs are out of budget for now. Planning going forward is to redo the flat roof as best as possible and a builder to quote and design as mentioned before. With the quantity of lead on the roof, the scrap value is impressive enough to get new osb, insulation and rubber roof to tide us over until the main redesign can happen. Currently leaking like a sieve. What I could Do with is help on the best insulation solution for this meantime. Currently a cold roof with no insulation. Option 1 Warm roof, replace existing osb3 18mm, damproof membrane, 50mm PIR, 12mm osb3 and rubber, raises the roof 65mm out of availible 75mm. Cant raid much more due to the Velux in the roof and the slate line. Could put in rock wool below the roof im the void .. Option 2 100mm insulation between rafters leaving 50mm air below new 18mm osb3, further 50mm insulation board below the rafters, and ecowool on the plasterboard roof and damp roof membrane Option 3 Rubber, 12mm osb3,50mm insulation, damproof membrane, 18mm osb3, airgap to eaves as in a cold roof, 100mm insulation, earthwool plasterboard (thought was that the extra insulation on the warm roof side might prevent the cold air penitration on the 70sqm flat roof, if only a little) Any thought or problems you see here for any option. New pitched roof may have to wait a few years, but the cost of the lead as scrap should cover the majority of the supplied meantime. Any pointers where I might be going wrong or could improve meantime. We have had 3 quotes from builders so far.

So the main bedroom has an open roof space into the eves of the roof, meaning changing the hip slope would have to change the inside of the house as well... I know the overall look would be far better but I feel with a 4 month old its going to be too much of a change and unfortunately cost at this stage. (pending lottery results tonight I guess.. ) If I could do the work myself it would be great, but I think we are quickly getting into more than a one man job. @Radian any idea on what is required to make this type of change. planning, structural engineer sign off etc? Will get photos..

@Radian thats great, i actually had to double take and spot the difference there. it would be far more fitting with the house I agree. only issue i see is without changing the pitch angle of the roof over the bedroom we would have to alter the bedroom roof as well on the main house. great idea though. We could of course have a different pitch on the back of the house to that on the gable end of the house. not sure how that would work. what do you mean regarding the wording of the house and shallow pitched roof.

So these are the wall dimensions, there is a 250 overhang of the roof on all sides apart from the side with the green arrow, it is only about 100mm Where the red arrow is there is a step out for the main bedroom wall approx. 100mm , but I thought that i could use this space for external insulation and render. taking it out to the main body of the house. the height of the roof along the bedroom wall is lower than that of the flat roof as there is a slope in that see attached photo. this difference is about 680mm. the gable end of the main house (bedroom wall) has a triangular sloped roof, sorry I don't know the correct name for this. I know this is vague, but to do an apex roof, what would you expect the cost to be? Any idea on what planning would be required? or would it just be a building warrant. Remember we are in Scotland. Anyone wanting to come give me a hand , free bed and board and i might even open a special whisky for you!

Thank you for this, it make it so much more bearable to understand than online google solution finding. SOO, the house is a Biomass boiler, Put in by the previous owners. Futureproofing would mean air sourced or ground sourced heat pump (we have enough land for this so is a potential), however the floors are concrete so also means pulling up the whole house unless we want mediocre radiator solution... There is electric floor heating in the En-Suite and shower room and kitchen, No idea why they did not go for hydronic, En-suite is a consideration for this as we would like to replace it at some point, the rest of the rooms I think will have to remain, and get very little use because of the cost to run them. Radiators are plumbed with heat going in at the top and out at the bottom (on the same side of the radiator) and TRVs placed on the out flow, and in the same room, on another radiator on the inflow.... I mean come on! Even flexable braided hoses were used to plumb in one radiator which inevitably blocked as there would appear to be no inhibiter in the system. So the house is in great condition (appart from minor issues), and just a half assed job on the extension by the owners 2 owners ago. (Ironically I know where they live , They also stole from the queen by removing a old telephone box from our grounds! ha ha. There are quite a few rubbish finishes around the place that lets the house down but they are only finishes so can be repaired over time) Regarding your images above, the new proposed roofline to the right, is this essentially a flat roof from the Apex of the main house roof or would a new apex roof meeting perpendicular be another option? How do I account for the step in the glazed wall? on your design or Perpendicular design (other than get planning to remove the step and make is square). Removing the velux is not an issue, we could essentially put this in again or another lighting source such as a fixed roof window.

Wow, what an explanation @Iceverge. Thanks man, and you are right, my daughter and fiancé are my life and I never thought I would have kids. I guess 40 isn't too late to find someone that's right for you! And I could never have dreamed of having a house like this, incredibly lucky to have bought a house cheaply in a good area a few years back and the prices rocketed because of it being in a desirable school area. Then meeting the other half who had done similarly. So in answer to your points: 1. You like the house and the area. Absolutely, We bought the house in March 2022, it is a dream. Location is almost at the top of a low lying hill but 2 fields from a light aircraft landing field. Not noisy so not a concern. however it is mighty windy. 2. It is sufficient in size and layout for your needs. I moved from a 800sqm house to over 2600sqm so yes we have space for the three of us! 3. A budget for a knock and rebuild is completely off the table? At the moment the extension is only a en-suit, dressing room, with laundry and cupboard, we don't need it to be glorious, but we do need to improve the icy cold in there. 4. It suffers from poor ventilation. I have a manrose MF150T to go in. enough draw to inflate a hot air balloon. 5. You have lots of drafts, lots of outside doors, lots of sliding patio doors. (Notoriously draughty) Main bedroom is patio sliding door, its going to go and become a French door, We have the orange shutter door between the bedroom and bathroom and shutters over the bedroom door as well. the glass in the en-suit and dressing room i think is less then half the cold issue, the uninsulated roof is the pain. 6. The house has awful thermal bridging, especially the extension with all the steelwork etc. the structural poles, are literally acting as air-conditioning units on lower than low, with the wind blowing past them they are drawing the heat out of the place. 7. You are relatively confident regarding DIY etc I fully stripped out my last house and redid plumbing, kitchen bathroom, some wiring and had it certified, so happy enough. also a mechanical Engineer in oil and gas so yea im confident i can do most things. 8. You need to live in the house whilst any work is ongoing. Yes, there is a main bathroom so the dressing room and En-suit can be out of action for as long as needed. 9. The house swallows heat like there is no tomorrow given it's large outside surface area vs internal area. (form factor) 100%, especially the extension. Main house with stone walls actually retains the heat well. 10. You need to live in the house whilst any work is ongoing. Yup 11. You will be able to afford over a few years to get it to a good standard. Just not in one go. Yup 12. You're off the mains gas network? No mains gas or sewage. we have gas only for the kitchen hobs, and a septic tank. Solar on the roof, intention is to get more and batter storage independent of the main house so as not to affect the feed in tariff. I don't know much about Bregs, especially in Scotland. However in practice it's unlikely anybody will stop you. Tell the neighbours how bad it is, with the baby etc and they'll be lightly to support you rather than call the council. The neighbours are 3 fields away and we are surrounded by a fence line of 200 year old trees. i dont have a clue where to start with who i need to speak to regarding planning other than the council 1. That flat roof has to go. Take it down and scrap the lead. Erect a proper pitched roof integrated into the original house. Do you mean to the same height as the main house roof? What would be the benefit of adding this? Assuming you have at least 10 deg pitch you can use roof tiles which are cheap and durable. 8% at most currently and we have a velux in the main house roof over the top of the flat roof to give light to a rather dark hall way. we would need to account for this in a full pitched roof. and cost I have no idea what this would be. Max i could rais the roof to the house side would be 100mm. which should give a greater % run off. Leave at least 600mm overhang at the gables/eves. Insulate it all with 400mm+ of insulation. Rolls of mineral wool are cheapest but a blown one like cellulose or Glass Mineral Blowing Wool will be easier to fit and re settle when you put in ducting, pipes and wires at a later date. Would hard insulation be better, I would rather spend more for something better if we are retaining the flat roof... 2. When budget allows strip the original roof and with a bell cast extend the eaves and gables at least 600mm also. Sorry, I'm no building expert, what is a bell cast? 3. When the money allows for new windows and external insulation go ahead and do this, You can do one wall at a time if budget is constrained. Take the insulation around the outside of the steel poles and existing stone walls. You can continue living in the house while this goes on. Install the new windows in the insulation layer. I guess I have to ask, will I need planning for this? I assume I use external hard insulation and then roughcast onto that. W cannot insulate the stone part of the house externally as far as I know, it would dry out the stone too much and stop the house breathing. I know I can insulate internally with a fibrous board and lime plaster render though as I helped family do this to their home. Good quality PVC are fine, compression seals are vastly superior to brush seals so avoid patio doors, bifolds and sash windows. Absolutely 4. Install some kind of ventilation system that draws air out of all wet rooms continuously and vents it outside. This can be done now, a decent inline fan, a silencer and some ducting would be enough to get you started for a few £100. Only thing I'm certain about, Ha ha link to the house to give you a better idea of it all https://www.facebook.com/ResidenceEstateAgents/posts/6613161455421700/

the extension with ensuit and dressing room is a block brick wall only 300 ish thick

Old stone farm cottage , single story, fully detached, thanks it is in the country with fields and surrounded by trees on the fence line. love it here.

@HughF , I would agree however cost is out of my possibility right now. With a wee baby we just need it warmer and no damp. Cheaper in the long run but just cant manage it right now. The old house is 3ft thick stone walls, so there is no likely hood of passing building regs on that. Does anyone have any idea on how building regs work in Scotland as internet searches only shows up for England, and Right now I have no idea if I need to inform local authorities in order to change the roof from lead to rubber or anything else. I read that England requires a flat roof to fall under new insulation building regs if replacing more than 25% of it....

The photo with my hand is indicating about 100mm that there is potential to warm roof insulate, but that would include the 11mm osb and rubber. on the sketch the chevron is not part of the house. BIG thanks to everyone on this. Nice community to help folk.

some more images inside and a sketch with sizes in meters.

So attached below are the outside photos. @MJNewton it is baltic in here. glass to the touch is icy cold so the glazing is shot. ironically Everest glazing and dated 2007, but as everest went into receivership 2020, apparently due to covid, i laugh, and reopened as Everest 2020 limited, they no longer honour their 20 year warranty on glazed units... so your warranty is worth hehaw. Grey posts at the corners are the steel supports as seen inside the room. so no insulation at all on those. the roof cavity is at a guess from sticking my head in the hole 150mm no more at the edge of the building and the cavity increases to the house side to 250 potentially 350 at a guess. not enough to really crawl in. Plasterboard is your standard paper backed. no foil backed or water resistant at all. and same in the bathroom. I guess my questions here are, To replace the roof do i need building inspections do i need to get planning permission? can i change the positioning of the windows under the roof without needing to get planning? if i decide to go inside the poles or outside. issue moving either way is the wall is in line with the outside of the pole so moving either way i would have to build to the outside of the wall or inside into the room. @Iceverge standard height room 2.4m @Nickfromwales without sounding like the churchill dog Oh yes, only happens under bad weather from west or north @Radian what is your suggestion on correct plasterboard type, and vapour barrier. as i'm going to have to do this one myself as getting outcosted with requirement for new windows and roof. @PeterW are you able to advise on the exspance fro 150mm joist, luckly but possibly not, there are walls within the roof space, there is the bathroom, dressing room and a laundry room so internal walls in a T shape as well as a large cupboard. I have no idea how and if the walls are acting correctly as a supporting wall. @Conor @JohnMo and @ anyone else how would i correct these mistakes. as best i can. I am an able bodied person with DIY and much more so happy to take it all on. Any advise on building regs in scotland would help too, inc need for planning. and anyone done a rubber roof able to give pointers on the skylight velux as well? brands of products inc insulation rubber and glues as well as vapour barriers please give an opinion. looking to start in april or march

Hi guys. first off thanks for the help. Second sorry for the delay. I have been having Window quotes done. Everest 25k Anglian 15k Local 12k I will get a heap of photos tomorrow. Roof depth is 300mm joists 150mm length of roof 9.3m slope or width of roof 7.5m. Interior height 2.4m Plasterboard I think is generic. Ventilation fan in bathroom is tiney so have a 150mm manrose to go in. Haven't used this bathroom in winter and roof leaks only in severe weather. Terribly wet osb. Dont think I can warm roof Insulate as the main roof has a velux in it and is only about 100mm from the top of the lead roof. There is also a raised velus in the lead roof. Thought here is Raise joists by 50mm battens. Put 100mm hard insulation ( please recommend brand for me) between the joists. Leave an air space of 50mm. 18mm marine grade ply or would I be better with grade 3 osb or grade 4 On the cold side of the joists the rubber onto that No capture barrier on this one... or where would I put it for a cold roof? Or 18mm marine ply on joists Altrix 600 or another vapour barrier ( please recomend) 50mm hard insulation on ply 11mm osb 3? Or 4? the the EPDM? can i put more insulation between the beams with air gap to underside of the play or is it worthless? currently there are air belts as its a cold roof so I guess on a warm roof I would seal those off? yes having to do this myself... roofer with led 15k roofer with rubber 13k Windows 15 to 25k i dont have that ... simples. Photos to follow in detail tomorrow

@JohnMo what you say thats how your steel work was done do you mean the same as mine or @connor described?

so photos below of the area. the bathroom is all glass with the steel work as described at the corners. And the dressing room is similar. the steel work is internal and external so placing the windows around them would mean increasing the size of the extension and no doubt planning permission. photos of inside the roof space are as poor as they seem. ripping down and starting again would be ideal but we just don't have the ready funds for that

Hi all, I have an issue on an extension of a house I bought last year where a flat roof extension has been installed with two walls in large glass panels. This is for an ensuite and dressing room. There is a step in the longest glass wall that is also glass. This leaves 3 steel uprights at 3 corners. (no we are not overlooked and having a garden with trees all around leave you happily having a bath with the blinds open:) ). Issue is the flat roof and thermal bridging of the steel Columns. I expect that there is some steel work in the roof above the windows but there is no access to see other than a hole I cut to see what insulation is up there. And I expect the roof steel is also uninsulated. Answer to insulation, non that is doing any good, as it is not held in place and as it is board insulation its fallen down leaving air passage. And shoved between joists as a cold roof that pointlessly holds insulation. The roof is covered with lead and is 9.3m by 7.5m slope is along the shortest side. There are no steps in the roof and joints are double lapped, incorrectly. Roof is OSB and is rotting as the laps of the lead is not covering enough. Short side is it needs to come off. Regarding the thermal bridge on the upright steel, the windows are fitted directly to the steel poles... So the double glazing is pretty useless. We are looking to getting new windows and we need to insulate the poles as best as we can. What would be the best recommendation, minimum insulation thickness vs best thickness? I am going to assume we can use a ridged board insulation and then should use some form of water proof covering over the top, I had thought of using the lead from the roof in some fashion, but how best should I construct the covering to provide a good seal for the new windows? The roof is a totally different issue, as height is a problem and the only flow of air will be back into the main roof of the house which I expect will not be the best airflow for a cold insulation, as the beams used are small, I think only 150mm possibly 100mm. There are small soffit vents approx 70mm. We are thinking of replacing with a warm roof, however due to a vellux window there is a height restriction, also there is a raised Velux in the middle of the flat roof. If there is a suitable solution for a cold roof we may consider that. The final covering will likely be EPDM as the cost of led work and required height raise of 225 to account for the required steps is not possible due to the vellux. If we keep the insulation to max 150mm we should be able to avoid the window.. I hope to do the work other than the EPDM myself, simply due to cost, so material guidance is also sought after, so far thought is 18mm exterior WBP ply. Alutrix 600 barrier. 120 Kingspan, or if anyone can recommend better/ cheaper, then EPDM. I would have liked a hard covering on the insulation as we have over hanging trees, but according to timber development uk this is no longer recommended as the EDPM will trap moisture between the vapour barrier and wood will rot? Someone please tell me if I'm wrong as this is all my own research so not 100% I will put some photos up tomorrow so folks can see. Many thanks, Matt