Mystifying damp issue

[monica357]

Hi All,
Hope all is well with everyone there.

Well it's been a while, but feel the need to post an update. I have had a difficult time of it, been let down by builders, been ill and two years on still in the same position, but some things to report. The condition of my floor and hearth are exactly the same. Let's face it there has been plenty of time for everything to dry out. I keep an eye on humidity. I have dehumidifiers, windows open as much as possible. I bought Peter Ward's new book but didn't contact him, I just thought I'd monitor everything myself. I have learnt that the dewpoint plays a part measuring moisture too. Bur that's not all I've learnt.

Next week I am hoping for a builder to begin work on the floor and section of constructional hearth. The floor will be lifted and all debris cleared to assist ventilation. This might throw up undiscovered issues with the floor, but at the moment the plan is to replace any floorborads where necessary, treat or replace any dodgy joists, insert any damp proof membranes where necessary. As for the section of constructional hearth which sticks out beyond the stone fireplace, which I want to keep, the idea is to dig it out and replace with concrete, specifically they say:
Grind down and chip out area of old hearth that extends past the new hearth

Take old hearth down to a level to allow for 20 mm of airflow underneath the floor boards.

Does this sound about right?

I am having the chimney swept as well next week in preparation for a new gas fire. And electrics resited . Later some corrective plastering and decorating.
My main question is about the hearth. I attach a picture as a reminder.
Look forward to your thoughts.
Monica

 

[Cubist]

Hello Monica and welcome back.

Sorry to hear that you've been unwell and I hope you are fully recovered. Coincidentally I've been away myself for some considerable time and have only recently had an opportunity to resume my participation here. One of the little foibles of the site is that, because every new contribution appears in chronological order and, as most of us may make multiple comments on a range of topics during the course of a session, then many new contributions may be very quickly pushed down the displayed list. It's nothing to worry about and all you need to do if you want to solicit some feedback is to 'bump' your item back up to the top by adding another comment. Oftentimes another member will do this for you if they see that your item has drawn no input.

However, you also have to remember that many of us regulars are men in our middle or later years who, like the callow youths we once were, are frequently attracted to the bright new flashy model that just arrived on the scene - rather like kittens in that respect - or more accurately perhaps, beset by short attention spans coupled with weak bladder control. I plead the 5th on that but hope this helps to get some advice for you by 'bumping' this item back up the list.

Be ready though, it will soon begin sinking again.

Cheers,
Cubist

 

[monica357]

Hello Monica and welcome back.

Sorry to hear that you've been unwell and I hope you are fully recovered. Coincidentally I've been away myself for some considerable time and have only recently had an opportunity to resume my participation here. One of the little foibles of the site is that, because every new contribution appears in chronological order and, as most of us may make multiple comments on a range of topics during the course of a session, then many new contributions may be very quickly pushed down the displayed list. It's nothing to worry about and all you need to do if you want to solicit some feedback is to 'bump' your item back up to the top by adding another comment. Oftentimes another member will do this for you if they see that your item has drawn no input.

However, you also have to remember that many of us regulars are men in our middle or later years who, like the callow youths we once were, are frequently attracted to the bright new flashy model that just arrived on the scene - rather like kittens in that respect - or more accurately perhaps, beset by short attention spans coupled with weak bladder control. I plead the 5th on that but hope this helps to get some advice for you by 'bumping' this item back up the list.

Be ready though, it will soon begin sinking again.

Cheers,
Cubist

Thanks Cubist. I'll look out for any advice. I'm no chicken anymore either but still pretty on the ball!!!

 

[monica357]

Just thinking, Cubist-how do I 'bump' the item up to the top as you say? Sounds crazy I know, but maybe I am!

 

[chrisfraser05]

you just did bump it up!

 

[Cubist]

you just did bump it up!

I'll admit to being a trifle crackers but.... to claim we're all crazy now comes with a terribly cringeworthy Top of the Pops flashback.

 

[Eric56]

Mama?

 

[monica357]

Droll!

 

[Cubist]

Sorry about that Monica, but sometimes my sense of humour gets the better of me. Regarding your builders proposals for the hearth; the plan seems sound to me and anything they can do to improve air-flow around the floorboards and joists will be helpful. You need to be aware though that any fire/heat source in that hearth will inevitably draw cold, and therefore moisture laden, air from below floor level as well as above. Consequently it may be an idea to ensure that your builder treats the cut ends of the boards to inhibit their ability to absorb moisture and prevent/inhibit future staining or rot.

 

[monica357]

That's great Cubist as they are coming tomorrow, which is why I was so anxious to get your take on it. Having some electrical work done today. I'll probably have more questions soon as work is now underway, after so long!

 

[monica357]

Hi again,
Wondering what your view is on insulation under floor. I think it reduces ventilation. Problematic in a 1898 building I feel. It's just all we seem to hear about now. Surely thick carpet and underlay help with that? Monica

 

[Lacan07]

Hi again,
Wondering what your view is on insulation under floor. I think it reduces ventilation. Problematic in a 1898 building I feel. It's just all we seem to hear about now. Surely thick carpet and underlay help with that? Monica

You'll hear various opinions on this, I'm not a fan of it and I know plenty of builders that aren't very keen on it either. Using breathable materials like wood fibre board, as opposed to the standard rigid foam, board might temper some people fears but my main fear (and my builder friends) is how wet or damp it may get and therefore be rendered ineffective.

For me I'm concentrating on sealing draughts elsewhere and leaving the floor bare. I was once told by a retired builder on another forum that when the space above a suspended floor is heated and therefore warmer than the void below a strange phenomena occurs whereby the cold damp air gets sucked out the air bricks.

 

[monica357]

Well, builders are here now and lifting floor to clear away debris. I have discarded the idea of insulation-when in doubt, leave it out! I never really had an issue with extreme cold in that room-cold comes from the kitchen next door to it. So, carpets and underlay, maybe thermal or maybe what I had before, average thickness, is my way to go. There's a lot of strange phenomenas around that room anyway so I want no more! The builder actually did say carpets and underlay were the alternative so he wasn't trying to sell me insulation-a lot would.

 

[Lacan07]

Well, builders are here now and lifting floor to clear away debris. I have discarded the idea of insulation-when in doubt, leave it out! I never really had an issue with extreme cold in that room-cold comes from the kitchen next door to it. So, carpets and underlay, maybe thermal or maybe what I had before, average thickness, is my way to go. There's a lot of strange phenomenas around that room anyway so I want no more! The builder actually did say carpets and underlay were the alternative so he wasn't trying to sell me insulation-a lot would.

I doubt he'd want to do it tbf, and if he did I'd have even less faith he'd do it properly.

 

[Eric56]

This!

This is why I find this forum to be extremely valuable. I like to hear a range of opinion and experience.

Rather than the disinterested shrug from someone who is limited to what cheap materials they can get at Screwfix. They also want to profit off the distress of others offering a quick fix solution.

This is why we all end up doing things ourselves. If is harder and takes longer. And you make mistakes and feel frustrated along the way.

But its better than paying good money to people who really arent that skilled or experienced.

 

[DaveG]

Hi Monica, I read your mention of Pete Wards book. I also use this book like it’s gospel for trying to address my own damp problems having moved into an 1870s stone build recently.
It caught my attention you mentioned a gas fire. If you don’t have high humidity levels (like I do) it may be a non issue to you but if you’re not already aware, gas is a rather wet fuel source and burning it can add a not insignificant amount of moisture to the room.
All the best with the work. I really hope it is resolved for you.
Can I ask, where you are adding dpc? Is this just between contact points of wood beam and foundation? Asking selfishly as I embark on removing a concrete filled floor to return it to suspended once more!
Thanks
Dave

 

[monica357]

Hi Monica, I read your mention of Pete Wards book. I also use this book like it’s gospel for trying to address my own damp problems having moved into an 1870s stone build recently.
It caught my attention you mentioned a gas fire. If you don’t have high humidity levels (like I do) it may be a non issue to you but if you’re not already aware, gas is a rather wet fuel source and burning it can add a not insignificant amount of moisture to the room.
All the best with the work. I really hope it is resolved for you.
Can I ask, where you are adding dpc? Is this just between contact points of wood beam and foundation? Asking selfishly as I embark on removing a concrete filled floor to return it to suspended once more!
Thanks
Dave

Hi Dave,
Well the floor is done- a mix of new floorboards and the originals. The rotten joists were replaced but we discovered the plates-I thought these were joists! were also rotten at the wall ends so that was sorted. There was some joist replacement and a lot of treatment painted on. Those damp proof membranes were put on ends-anywhere where the wood touched masonry. Under the sub floor which measures about 9 inches the foundation is concrete and all debris etc was cleared as I wanted. As for the fire, well yes it is gas. It's one of those Nu flame imitation coal models. The one there will be replaced with similar and whole backing plate cleaned etc but that's probably the last job to be done. That room does get quite high humidity being next to kitchen on one side and bathroom on the other, but now ventilation is improved, windows regularly open and I have a dehumidifier which I use sometimes. The fire had been there for 20 years and before that there was a gas radiant fire. No real issues- the damp issues I had were created by my neighbour's burst water main pipe. I paid a fortune to get internal walls re rendered and didn't really need to as their leak was discovered after I had it done. As for the section of constructional hearth-plan changed slightly- they grinded down about an inch , put in a damp membrane and put floorboards up to the stone hearth of the fire surround. I wanted it to be clear that if it doesn't work it can be undone. It'll be months before any carpet goes down. Next thing is minor and corrective plastering-the walls were lime and two walls didn't need re rendering so I'll be expecting lime on those, the other walls have a gypsum topcoat unfortunately but that will have to stay.
I didn't thimk you anticipated a potted summary of my jobs but you've got it. I hope I've answered your main question.
This site is great isn't it. I have had so much help from the experts. Monica

 

[monica357]

HI, Got a question about lime plastering. I have had the electrical points moved to the wall from skirting boards and these walls are lime. I have had three plasterers quotes. Two have described proper lime plastering which is slow drying etc while one talks about a lime backing coat finished with a gypsum multi finish topcoat . I don't think this last one is right-can someone give an opinion please.