Advice needed - How this entrance can be thermally insulated?

[baldkev]

Hello @baldkev


This sound like an interesting approach. However - given how small my now "ex-rain porch" area - if I cover it with something impermeable, would not this just cause any moisture from the walls and ground to travel a bit further into the house and surface on on the original internal plastered walls as

to address the dehumidifier and drying options again, i wouldnt bother. The brickwork ( im assuming ) is from the original porch and unlikely to be a cavity wall, so it will lerp getting wet. The tiled area is an external bit of ground, without dpc, so damp will continue there too.
You need to have a tanking solution to stop the damp. End of.

After that's done, there will only be condensation from the plastic window / door setup sometimes. This is where the temperature difference inside meets the cold air outside and creates condensation. In most modern windows, theres a thermal break ( mentioned earlier ) with the odd weak point, like a letter box, or sometimes where frames are joined together etc.
I believe the insulation tight onto the cold surfaces should stop the condensation / dew point being inside, and any external moisture should stay in the brickwork / under the tanking under the porch

 

[BillHoughton]

I'd change my mind and put a door back where the original one was, without removing your new one. You'd get what is referred to here in the U.S. as a "vestibule," and it makes a huge difference in keeping the cold out when done right. Do proper sealing with your door insulation and think, in designing it, about moving furniture in and out (for instance, size the door to allow for it, and put it in line with your new door). I agree with the comment that what you've likely done is bring inside the house walls, floor, and possibly ceiling that never intended to be inside and are bringing in lots of heat through conduction.

 

[fleyh]

I'd change my mind and put a door back where the original one was, without removing your new one. You'd get what is referred to here in the U.S. as a "vestibule," and it makes a huge difference in keeping the cold out when done right. Do proper sealing with your door insulation and think, in designing it, about moving furniture in and out (for instance, size the door to allow for it, and put it in line with your new door). I agree with the comment that what you've likely done is bring inside the house walls, floor, and possibly ceiling that never intended to be inside and are bringing in lots of heat through conduction.

Hello @BillHoughton,
It is a fair suggestion, especially if you have not seen inside of my house. The issue is - we got fed up with not being able to enter the house properly. Where the old door used to sit - it left almost zero space to take the shoes off. When 2 persons are entering the house - only one could come in, the other had to wait outside till the first one takes their shoes off and proceeds into the house. Only then, the space inside (behind the door) could allow second pair of muddy shoes to enter.

and think, in designing it, about moving furniture in and out (for instance, size the door to allow for it, and put it in line with your new door)

Good advice. Thank you.

 

[BillHoughton]

In going back and looking at your picture in the original post, I'm not sure you've got enough depth to swing the new door fully open if you put the old door back; so, no, maybe not such a good idea. You've had plenty of useful advice about insulating/sealing your newly-inside wall surfaces. Always interesting how projects make more projects...

Incidentally, is your new door sheltered - is there a roof over it? If not, when it rains, you're going to get water on your entry floor when you go in and out. Speaking of projects begetting projects.

 

[fleyh]

Hello @baldkev

The brickwork ( im assuming ) is from the original porch and unlikely to be a cavity wall, so it will lerp getting wet.

I am sorry I forgot to explain - the original rain porch was recessed into the house rather than built outside of the house.
The new door is now flush with external wall on the front of the house.

I am led to believe that this house has a standard for 1970s build cavity wall which was insulated at some point.

Does what I wrote above change your assessment of the situation? Namely - do you still think that dehumidifier is of no use in this instance and I should/could proceed with tanking and then insulation straight away, without waiting for walls to dry?

 

[fleyh]

In going back and looking at your picture in the original post, I'm not sure you've got enough depth to swing the new door fully open if you put the old door back; so, no, maybe not such a good idea.

Indeed. When the new door was installed (right before the old one was removed) there was no way to open the new door fully.

You've had plenty of useful advice about insulating/sealing your newly-inside wall surfaces. Always interesting how projects make more projects...

LOL. Yes.

Incidentally, is your new door sheltered - is there a roof over it?

The new door is flush with the front wall of the house. It is exposed to the elements the same way our patio doors are and we have had no issues with the patio doors. Also, there have been several heavy rains (with the wind blowing towards the new door) since the new door was installed and (so far) it does not look like the rain water is able to get in. So hopefully there is at least one potential issue is avoided.

 

[Doug71]

Even though the house has cavity walls the new position of the frame means the brick walls in question actually act as solid walls because there is no break between the now internal brickwork and external face of the brickwork. Damp and cold can transfer through the brick from the outside to the inside which is potentially the problem.

 

[baldkev]

Hello @baldkev


I am sorry I forgot to explain - the original rain porch was recessed into the house rather than built outside of the house.
The new door is now flush with external wall on the front of the house.

I am led to believe that this house has a standard for 1970s build cavity wall which was insulated at some point.

Does what I wrote above change your assessment of the situation? Namely - do you still think that dehumidifier is of no use in this instance and I should/could proceed with tanking and then insulation straight away, without waiting for walls to dry?

To be clear, is the brickwork ( that we can see from the inside ) a single skin, or cavity wall? If cavity wall, exterior damp ( rain ) shouldnt soak into the interior leaf unless wall ties are wrong or cavity fill is absorbent, transmitting the damp.

The original construction wouldn't have had insulation, so what was used to subsequently insulate it? Some cavity fill materials were extremely poor, even causing damp retention etc.

In my opinion, whatever the answer to the above questions, if it were tanked to stop moisture ingress, then insulated, the moisture content of the air would find equilibrium with the rest of that zone ( original hallway in house)
If the moisture ingress is stopped, any residual/ extra moisture in nearby interior walls ( caused by the current situation ) should disperse.
You could use a dehumidifier but the retained warmth after insulation, will draw it out fairly quickly on its own. Most houses i would guess, are heated to 18 to 21° through the winter, some higher.
Dehumidifiers were suggested to dry out the brickwork, where the majority of the damp is, but all that will do, is suck damp into the newly dried bricks when it rains. If the tanking is done, that moisture doesnt come in.... but you then have to insulate it to stop the wall condensating.

 

[cowtown_eric]

This is a sideways photo of our front door (side windows on top) taken with an inexpensive android compatible thermal camera. You can see the blue, which is cold...not sure of the thermal colour gradient..

Nowadays, I would take a much cheaper laser thermometer to more accurately asses what is cold and what isn't before I'd decide where the problems lie!

Many years ago, a coworker described a problem similar to yours, and after years discovered that when built, there was no insulation in the top of the projection

Eric in the colonies , now watching our -30 C weather move on to the inspector in sask, Mb Ont, Que.

 

[Jameshow]

View attachment 149729

This is a sideways photo of our front door (side windows on top) taken with an inexpensive android compatible thermal camera. You can see the blue, which is cold...not sure of the thermal colour gradient..

Nowadays, I would take a much cheaper laser thermometer to more accurately asses what is cold and what isn't before I'd decide where the problems lie!

Many years ago, a coworker described a problem similar to yours, and after years discovered that when built, there was no insulation in the top of the projection

Eric in the colonies , now watching our -30 C weather move View attachment 149729on to the inspector in sask, Mb Ont, Que.

Cold is blue, red is hot surely!!

 

[MikeJhn]

A damp expert (a proper one) once explained to me about how long it can take for walls to dry out and how much water there can be in them.

We were talking very damp old walls so not quite the same but what stuck with me was he said it's similar to leaving a bucket full of water stood in a room and waiting for it to evaporate, which I imagine would take quite a while!

That theory would only work if the bucket had no sides and the bottom was porous.

 

[fleyh]

To be clear, is the brickwork ( that we can see from the inside ) a single skin, or cavity wall? If cavity wall, exterior damp ( rain ) shouldnt soak into the interior leaf unless wall ties are wrong or cavity fill is absorbent, transmitting the damp.

I believe this brickwork is a cavity wall.

The original construction wouldn't have had insulation, so what was used to subsequently insulate it? Some cavity fill materials were extremely poor, even causing damp retention etc.

Yes, original construction did not have cavity insulation.
I can not say about this current house, but neighbouring houses had cavity wall insulation done by filling the wall cavity with some sort of foam about 10 years ago. I can only assume that in our current house the insulation was done the same way.

Here is my understanding of the current construction (if viewed from above):
- outer wall is brick
- inner wall - not sure, as I have never seen it without plaster

In my opinion, whatever the answer to the above questions, if it were tanked to stop moisture ingress, then insulated, the moisture content of the air would find equilibrium with the rest of that zone ( original hallway in house)
If the moisture ingress is stopped, any residual/ extra moisture in nearby interior walls ( caused by the current situation ) should disperse.
You could use a dehumidifier but the retained warmth after insulation, will draw it out fairly quickly on its own. Most houses i would guess, are heated to 18 to 21° through the winter, some higher.
Dehumidifiers were suggested to dry out the brickwork, where the majority of the damp is, but all that will do, is suck damp into the newly dried bricks when it rains. If the tanking is done, that moisture doesnt come in.... but you then have to insulate it to stop the wall condensating.

This is very helpful. Thank you very much for taking the time to go into these details @baldkev

 

[baldkev]

I believe this brickwork is a cavity wall.

Yes, original construction did not have cavity insulation.
I can not say about this current house, but neighbouring houses had cavity wall insulation done by filling the wall cavity with some sort of foam about 10 years ago. I can only assume that in our current house the insulation was done the same way.

Here is my understanding of the current construction (if viewed from above):
- outer wall is brick
- inner wall - not sure, as I have never seen it without plaster

View attachment 149747


This is very helpful. Thank you very much for taking the time to go into these details @baldkev

I'm specifically asking about the visable brickwork walls that the front door is inbetween.... are they cavity or single skin brick?

 

[Jameshow]

If you line it with either foil insulation or celotex insulation, then you will have a waterproof lining.

Any moisture that can get through that is negliable.

Insulation + plasterboard and ply floor would be best value tbh.

 

[fleyh]

Even though the house has cavity walls the new position of the frame means the brick walls in question actually act as solid walls because there is no break between the now internal brickwork and external face of the brickwork. Damp and cold can transfer through the brick from the outside to the inside which is potentially the problem.

Makes sense.
My assumption is - given that the contact area between the door and the outer brick is small the amount of water/moisture that can travel via that bridge is also small. And if I was to thermally insulate the walls then it should act as a barer between warm air inside and cold outside. So it does not sound like this is completely hopeless.

 

[fleyh]

I'm specifically asking about the visable brickwork walls that the front door is inbetween.... are they cavity or single skin brick?

If you mean areas where arrows point in the screenshot below then it appears as a single skin brick.

 

[Sachakins]

Given your diagrams, I think the chance of rain moisture regenerating back into the now inside wall is minimal, also the cold bridge area exposure is so small effect of drawing cold in will be minimal too.

Once these "new inner" walls get warm and dry out I believe that the problems you experience now will subside greatly. And still recommend dehumidifier and gently heat, then board and insulate as needed.

The tilled floor however needs more work. As others have mention, I think the only option is to dig it out deep and fully. Proper damproof, screed, insulation and top screed to level to internal foundation floor.

 

[fleyh]

Given your diagrams, I think the chance of rain moisture regenerating back into the now inside wall is minimal, also the cold bridge area exposure is so small effect of drawing cold in will be minimal too.

Once these "new inner" walls get warm and dry out I believe that the problems you experience now will subside greatly. And still recommend dehumidifier and gently heat, then board and insulate as needed.

Hello @Sachakins. Thank you. This is reassuring.

The tilled floor however needs more work. As others have mention, I think the only option is to dig it out deep and fully. Proper damproof, screed, insulation and top screed to level to internal foundation floor.

What would you call a "proper damp-proof" please?
Does this necessarily mean "tanking slurry" mentioned earlier in this thread or can it be something simpler, like this one: Capital Valley Plastics Ltd Damp-Proof Membrane Black 1000ga 3 x 4m

I realise that tanking slurry will likely give better performance, but it seems quite a bit messier to install than a plastic membrane.

Proper damproof, screed, insulation and top screed to level to internal foundation floor.

Could you clarify - what would be the function of screed below the insulation? Will it be required if surface under the insulation board is somewhat even/level and does not have large changes in depth?
I realise why top screed is required, but not sure why the bottom one is needed.

 

[Sachakins]

That damp proof membrane will be ideal. The screed/cement just an easy way to get a flat solid surface, hold dpm securely down and reinforce the base to lay the insulation onto.

You may find that when you dig out, there's probably only soil below. So treat it like laying a mini foundation block.

I had a similar issue when I opened up under a stairway. Found damp inner wall. When I removed the floor found old victoriana tiles laid on shale and soil. Dug out down about 6 inches, compacted, laid plastic dpm, screed/cement, celotex insulation, floor screed.

Did that about 12 years ago and never had any damp, cold spot or any issues whatever since. Still 100% dry and same temp as rest of floor and walls now.

 

[fleyh]

That damp proof membrane will be ideal. The screed/cement just an easy way to get a flat solid surface, hold dpm securely down and reinforce the base to lay the insulation onto.

You may find that when you dig out, there's probably only soil below. So treat it like laying a mini foundation block.

I had a similar issue when I opened up under a stairway. Found damp inner wall. When I removed the floor found old victoriana tiles laid on shale and soil. Dug out down about 6 inches, compacted, laid plastic dpm, screed/cement, celotex insulation, floor screed.

Did that about 12 years ago and never had any damp, cold spot or any issues whatever since. Still 100% dry and same temp as rest of floor and walls now.

This is perfect. Thank you @Sachakins, @baldkev, @Jameshow for the detailed steps and thank you everyone in this thread for your insights. It has been very educational. I believe I now have a good idea of what I have to do.

Merry Christmas