Advice needed - How this entrance can be thermally insulated?
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HOJ
Established Member
I can't relate the drawing to the picture, the walls # 6 & 7 are 3 bricks deep so that is about 655mm, that must be a projecting wall surely?
Hello @Doug71. Your assumption is correct.I was presuming it was something like this
One small detail - as you will hopefully also see from the photos I posted just now (see message above) - there is no "internal room" on the left because there is just no space for it. Area of "internal room" on the left hand side in your drawing is just brick as far as I can see.
TomGW
Established Member
I’ve just skimmed through the thread but a bit unclear of the setup. Is the house mid terrace or a semi? One side of the hallway will obviously be a room in your house but the other (stair) side is either outside or your neighbour’s house??
Is the new door actually flush with the face of the outside wall, meaning that the individual bricks that appear as half bricks inside are exposed, end on, outside? In an ideal world you should have broken this exposure to cold and damp by cutting vertically along the inside edge of the frame to create a gap to insert a vertical dpc and insulation. You could still do this but it will be a difficult, messy job. If you decide to ignore this bit you should at least water seal the brickwork all around the outside of new door.
Also, the dpm that extends under the door should have been a double layer with the top layer turned up the inner face of the frame. If it’s a single layer only you should have enough room to squeeze another dpc under the frame and seal both together with Tec7. If you don’t do this water will run down the face of the door & frame and be blown under and into your new floor.
Is the new door actually flush with the face of the outside wall, meaning that the individual bricks that appear as half bricks inside are exposed, end on, outside? In an ideal world you should have broken this exposure to cold and damp by cutting vertically along the inside edge of the frame to create a gap to insert a vertical dpc and insulation. You could still do this but it will be a difficult, messy job. If you decide to ignore this bit you should at least water seal the brickwork all around the outside of new door.
Also, the dpm that extends under the door should have been a double layer with the top layer turned up the inner face of the frame. If it’s a single layer only you should have enough room to squeeze another dpc under the frame and seal both together with Tec7. If you don’t do this water will run down the face of the door & frame and be blown under and into your new floor.
TomGW
Established Member
Photos posted while I typed.
As you have a detached house you should seriously consider removing the new inner leaf on both sides of the extended hallway as it’s just extending a cold bridge into your house.
As you have a detached house you should seriously consider removing the new inner leaf on both sides of the extended hallway as it’s just extending a cold bridge into your house.
Hello @TomGW
I have posted some photos (probably at the same time when you were writing your message), hopefully they can answer some questions.
There is a room on the right sight of hallway
I have posted some photos (probably at the same time when you were writing your message), hopefully they can answer some questions.
This is a detached house.
No room on the left side of the hallway, just brick, no neighbour's house
There is a room on the right sight of hallway
It is flush. Hopefully picture in this in this message makes it a bit clearer.
Understood. Thank you for the suggestion.
So the issue here is you’ve made an external wall internal now, and what you’re getting is cold walls and warm air and condensation. The “cold” you’re feeling is basically the brickwork slowly warming up and pulling heat from the inside of the house.
Four things to resolve :
1. There is no vertical DPC in line with the frame, so either there needs to be one cut or both internal and external faces treated with a water repellent 2 bricks past and 6 courses above the new door.
2. It is unlikely there is a DPM below the quarry tiles, and they are on concrete. To gain more room for insulation these tiles and the concrete should come up, blind with sand then a DPM laid with insulation over the top - unless you can get 60mm of screed in with at least 80mm of PIR insulation then suggest 2 layers of 18mm MR chipboard used as floating floor, glued and screwed in opposite directions / staggered joints. If using a floating floor then another DPM is belt and braces - should be sealed at the door threshold with either proprietary DPM tape or fleece backed butelyne tape.
3. Assuming you can lose 35-40mm either side then I would ensure the frame has been foamed properly in place, and then trim back the foam and seal the gap using a 100mm butelyne fleece tape lapped onto the frame by 20mm and then onto the brickwork. Now install PIR backed plasterboard with foam and fixings leaving a 3-5mm gap at the frame edges. Either tape and fill or skim the boards, can’t see how they meet the main house wall or thickness so you may get a step in the walls to deal with.
4. Seal the frame edges to the PB edge with good quality hybrid sealant such as CT1 and let the whole lot dry out and come up to “house temperature” for 3-4 weeks and stabilise before decorating.
The comments about letterboxes are probably based on old designs - the new ones in solid / insulated doors are the 3 part airtight type these days with double seals and brush inserts, not a lot gets through them.
@fleyh did you get a FENSA installation certificate with this ..?
Four things to resolve :
1. There is no vertical DPC in line with the frame, so either there needs to be one cut or both internal and external faces treated with a water repellent 2 bricks past and 6 courses above the new door.
2. It is unlikely there is a DPM below the quarry tiles, and they are on concrete. To gain more room for insulation these tiles and the concrete should come up, blind with sand then a DPM laid with insulation over the top - unless you can get 60mm of screed in with at least 80mm of PIR insulation then suggest 2 layers of 18mm MR chipboard used as floating floor, glued and screwed in opposite directions / staggered joints. If using a floating floor then another DPM is belt and braces - should be sealed at the door threshold with either proprietary DPM tape or fleece backed butelyne tape.
3. Assuming you can lose 35-40mm either side then I would ensure the frame has been foamed properly in place, and then trim back the foam and seal the gap using a 100mm butelyne fleece tape lapped onto the frame by 20mm and then onto the brickwork. Now install PIR backed plasterboard with foam and fixings leaving a 3-5mm gap at the frame edges. Either tape and fill or skim the boards, can’t see how they meet the main house wall or thickness so you may get a step in the walls to deal with.
4. Seal the frame edges to the PB edge with good quality hybrid sealant such as CT1 and let the whole lot dry out and come up to “house temperature” for 3-4 weeks and stabilise before decorating.
The comments about letterboxes are probably based on old designs - the new ones in solid / insulated doors are the 3 part airtight type these days with double seals and brush inserts, not a lot gets through them.
@fleyh did you get a FENSA installation certificate with this ..?
It is a single layer DPM unfortunately.
If I am able to squeeze another DPM (2) under the frame - should the rest of that second DPM be covering the floor (part covered in tiles at the moment) ?
Please excuse my ignorance - do you mind clarifying what you call "inner leaf"?
Hello @PDW125
Thank you for the detailed summary of actions. This is very helpful.
Yes, letter box looks exactly as you wrote - with double seals and brush inserts.
Not yet. Technically the installation is not yet complete. Our installer will be returning in Jan to replace glass in side panels - the ones his door manufacturer provided originally were not of the ordered spec (visually).
But installer is FENSA registered, so I assume we will be getting the certificate.
TomGW
Established Member
You should have a dpm covering the entire new floor but this should be on the warm side (top) of the insulation, not on the tiles with insulation on top. Just make sure water cannot penetrate under the uPVC frame and into the floor that’s above the damp proof membrane.
You have a cavity wall that extended in to the old front door position with the outer part (outer leaf) being brick. This outer leaf has now become an ‘inner leaf’ where it’s inside the extended hall but it is still connected to the outside. Some whole bricks are actually both inside and outside at either end and are bridging both cold and damp into the hall. On the side between the hall and living room this inner leaf (brick bit) is now totally redundant and is a source of cold and damp. On the other side (stair side) there must be a void behind the brick and then a cavity wall.
Jameshow
Established Member
I'd remove the outer brickwork that is now inside the house as this is causing a cold bridge.
If your not happy with the job how about calling in the window form who chances are will have a builder on the team who can do it at trade prices.
Otherwise get in a builder or two to quote.
Another source of information would be building control who might like to see poorly Installed upvc windows.
In my experience they have been very helpful.
If your not happy with the job how about calling in the window form who chances are will have a builder on the team who can do it at trade prices.
Otherwise get in a builder or two to quote.
Another source of information would be building control who might like to see poorly Installed upvc windows.
In my experience they have been very helpful.
HOJ
Established Member
We've all highlighted the main issue is the cold bridging, have a look at this document Thermal bridge it gives an overview of good practices, in this case as we now understand, your side walls and floor are potentially going to be a continued issue without drastic measures, i.e demolition, digging up and/or breaking open a gap in the cavity wall, I would strongly recommend you get a reputable builder to get eyes on to see if remedial works are viable & or feasible.
This is an extract from the FENSA website, makes interesting reading, and is pertinent to your situation::
"What's covered?
FENSA covers the replacement of external windows, doors, roof windows and roof lights in your home,
against the relevant Building Regulations. Note that the property must be sited on its original footprint,
and the use and size of rooms mustn’t be altered.
What’s not covered?
FENSA doesn’t cover the installation of windows and doors in new conservatories,
porches, new builds, new extensions, repairs (where frame not included) and commercial properties."
In my view in this instance a FENSA sign off isn't even applicable & yet more proof to me that FENSA is a complete waste, the supplier of your door is culpable for not having done an assessment of the circumstances and consequences, and not providing you with correct guidance in order to comply with elements of Part L of the building regs.
Extract from Part L:
Thermal bridging in existing dwellings:
4.19 When carrying out work in existing dwellings, care should be taken to reduce unwanted heat loss through thermal bridging. Thermal bridges can be limited in an existing dwelling by following the junction details from a reputable non-government database containing independently assessed thermal junction details, such as Local Authority Building Control’s Construction Details library. such as the document linked to above.
This is an extract from the FENSA website, makes interesting reading, and is pertinent to your situation::
"What's covered?
FENSA covers the replacement of external windows, doors, roof windows and roof lights in your home,
against the relevant Building Regulations. Note that the property must be sited on its original footprint,
and the use and size of rooms mustn’t be altered.
What’s not covered?
FENSA doesn’t cover the installation of windows and doors in new conservatories,
porches, new builds, new extensions, repairs (where frame not included) and commercial properties."
In my view in this instance a FENSA sign off isn't even applicable & yet more proof to me that FENSA is a complete waste, the supplier of your door is culpable for not having done an assessment of the circumstances and consequences, and not providing you with correct guidance in order to comply with elements of Part L of the building regs.
Extract from Part L:
Thermal bridging in existing dwellings:
4.19 When carrying out work in existing dwellings, care should be taken to reduce unwanted heat loss through thermal bridging. Thermal bridges can be limited in an existing dwelling by following the junction details from a reputable non-government database containing independently assessed thermal junction details, such as Local Authority Building Control’s Construction Details library. such as the document linked to above.
TomGW
Established Member
Is the wall section directly in front of the new bottom step of the stairs solid or stud? There’s obviously a bit of wasted space there that would make your hallway/bottom of the stairs a better shape. Removing that brickwork and enlarging the space would assist in getting rid of the cold bridge and allow you to insulate internally.
Below is a photo of what that space looks like at the moment
Half of the last stairs step had to be cut out to allow new door to open with hinges on the left. New door is installed in the middle of the frame.
Old door had hinges on the right and was positioned in the right half of the door frame.
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TomGW
Established Member
If you compare the outside corner of the house to the shape inside it will be obvious that there’s a void behind the brick that’s now inside the hall. Almost certainly the cavity wall follows the outer corner of the building and then another single skin of brick returned to the old door position. Behind that brick must be a void between it and the cavity wall that forms the gable of the house. I wouldn’t have been surprised to find that the bit that returns at the bottom of the stairs was simply a stud to close off the gap.
With your new arrangement it is now an awkward shape that serves no purpose. You have a few small gaps along the position of the old door frame so it should be easy to check that there is a conc block inner leaf behind, with a space between.
HOJ
Established Member
Does that exposed brick wall finish at ceiling level, presume it doesn't continue up into the room above, & do any floor joists land on it, (may be some trimming the stair well)
