Pappa

Hi guys 120 year old Victorian Terrace house in Lancashire, England... I've got some damp on the ground floor front room wall. This is an external wall with a 50mm cavity in between. This wall goes down all the way to the foundation underneath the basement. The skirting board has been removed and the bricks and mortar are wet. This is corroborated by a moisture meter. I can see someone has attempted to install a chemical DPC from the drill holes in the brick. Am I right in thinking this is quite an old system as modern chemical DPC is inserted at the mortar line? How can i differentiate whether this is rising damp or condensation? It might also be penetrating damp as I had some vicious Ivy that was growing through the uPVC window frames. The Ivy was removed about 1 month ago. Thanks in advance Pappa

70mm PIR between studs and 50mm over the studs on the external side. All fastened with tube washers. Should give me a u value of 0.17 W/m2K Thanks again P

How so? The stud thickness and spacing is spec'd by structural engineer so strength won't be an issue. There will be a rain screen on the external wall. ie. battens and counter buttons to provide a ventilation gap with render board mounted for rain proofing.

Thanks for the reply, thats right, its a single stud wall. There is no cavity for the wall insulation to meet the loft insulation. As the model shows, there is a massive thermal bridge at the wall plate with no way to insulate over it on the inside or outside. Thanks again P

Haha - I love your answer. To the extent I went and modelled it on Sketchup, please check the original link. However, it still suffers from the same problem as Model 1 (traditional pitched roof with insulation at ceiling level)... There is no way to mitigate the thermal bridging at the wall plate. Also, more generally, if you don't need the loft space insulated (which in this case I don't) I just feel like insulation at rafter level achieves the same thing but at a greater cost as it uses more PIR to go along diagonal rafters as opposed to horizontal ceiling joists. The end conclusion is the same either way, the room below is perfectly sealed thermally and hydrostatically. Happy to be corrected. Thanks again

Hi guys I'm trying to design a single story extension and was thinking about roofing structures with a view to maximise insulation. I've created 5 models: https://app.sketchup.com/share/tc/europe/RFf1yIra8Sw?stoken=g_uLQpD-6PkI1IdWUdy2VuAq5YQBVi8u8sePl-mi4LEE1gDgtJWcjI6y8nd3o1Lu&source=web There will be external PIR insulation along the entire wall which I have not included in the model. Model 1 is a traditional pitched roof with insulation at ceiling level. The problem is its almost impossible to remedy the thermal bridging at the wall plate. Model 2 is a traditional warm roof. The problem I have is that there is too much thermal bridging at the parapet walls where the ladder frame is. Model 3 is a variation of the above. Its a hybrid that allows me to enjoy the benefits of a pitched roof and a flat roof. Is Model 4 possible? In theory it is the most thermally efficient as it creates a perfect thermal envelope all around the building. However it relies on the horizontal ceiling joists being hung directly off the vertical wall studs. Is this possible? I'm wondering if I could notch the vertical wall studs and rest the horizontal wall stud in the notch with the usual mechanical fixings and adhesives. Model 5 is a variation of the above. Its a hybrid that allows me to enjoy the benefits of a pitched roof and a flat roof. Thanks in advance Pappa

Hi guys I'm building a small timber frame extension. This is what I want my wall to look like from inside to outside based on other designs I've seen around the internet: 15mm skimmed plasterboard. Vapour control layour 89mm stud with 70mm PIR in between 9mm OSB 50mm PIR. Breather membrane Render board What is the most thermally efficient way to attach the 50mm PIR from the outside into the OSB/Timber frame? How necessary is the breather membrane? Bare in mind I've got a VCL on the inside wall. How do I mount the render board on to the Breather membrane (or directly on to the PIR if breather membrane not required)? Can I skip the Render board, and render directly on to the Breather membrane (or directly on to the PIR if breather membrane not required)? I'm trying to do it this way because I have very limited space and I want to maximise the U-value per mm of wall thickness. Thanks in advance Pappa

Thanks for the comments Yes, I wan to design and install myself. I'll probably need the most amount of help on the design as I'll need to drill through brick walls (mostly structural) to get the ducting through. I'm also going to have wet underfloor heating (UFH) in the whole house so I need to figure out how the ducting will share underfloor space with UFH. Tbh, I'm happy to instruct a company if they can back up their price with service and quality. -I'm carrying out a loft dormer conversion and also a 2 storey extension to the rear of the property. I'm going to ask the architect to specify airtightness in these plans. -With respect to the rest of the house, I've got vent bricks dotted around. I'm going to seal these tight. -Its an old Victorian era property with Lyme based mortar between the bricks and Lyme based plaster. This is breathable, and I don't have a solution to make it airtight. -The best I could probably do is to paint the internal walls in a non breathable paint to ensure there is no diffusion of air (and heat) through the walls. -My wife is the weakest link. I've got no control over her opening the windows I'm afraid . That being said, This system will really shine through on very cold or wet days (which is most of the year) when she won't open the windows. Thanks again P

Hi Guys I just want to clarify for my dormer extension... Are permitted development rights removed completely in a conservation area or do I still have permitted development rights provided its not facing the highway? I want a dormer extension at the rear of the house which wouldn't be visible from the highway. Thanks in advance P

Hi guys I want to retrofit MVHR in an old Victorian Terrace that I'm currently gutting out and taking back to the brick. I intend to cover all ventilation holes for granular control using MVHR. Any advice or tips? Any recommendations on systems, manufacturers, or fitters? Thanks in advance P

Hi Guys I have a single storey structure at the rear of my house with an internal width of 2.2m. I'm looking to extend on top of this structure. I understand modern insulation standards require 100mm+ PIR. I don't want to go down the route of double skin wall with cavity because it is going to eat in to my already very narrow space. Which wall type will allow me to hit U values while taking up the least amount of space? I was thinking timber frame or single brick wall with 100mm PIR and cladding on the outside. Thanks P

Hi Guys Just started my project a few weeks ago. I'm in the process of gutting out a 168sqm Victorian terrace. Really enjoying the process so far, I've learned loads and looking to learn even more. Thanks P