Insufficient airbricks at rear - options?

[drpepe]

Hi all.

Since the last post we have had an airbrick situated under the front doorstep and doubled the size of the rear airbrick (see house plan in my original post)

We have also removed a quantity of loose damp soil from under the floor in the rear dining room and front lounge (increased depth by 10-20cm). The soil was level with /or covering wall plates in the pier wall and at the edges, meaning lots of the revealed woodwork was very damp.


4 weeks later however.... humidity is still high in the house (75-85%) and woodwork is still wet to the touch (visible on the wall plate in the picture below):

I guess my question is: how long does a house/woodwork with improved ventilation take to equilibriate, or does this already mean that what we have done is insufficient? (I will be adding the subfloor vent to the chimney, described in previous posts, in due course).

:?:

 

[MatthewC]

I think that if you've done the right things then you just have to be patient; drying out properly could take several months. In my house, once the roof and gutters were done (October-January!), it still took a couple of months before the damp chill left the atmosphere inside. Before we moved in four months later (after a good deal of warm summer), I thought it was dry and did some painting of internal panelled doors, but six months later I had a tidemark where the panels had contracted further!

However, do check that you have done all you can; because your house is terraced, I would be wondering if anything your neighbours had done was affecting it as well; i.e. if they have used gypsum over their adjoining walls, then the damp in the wall can only go your way and so takes even longer to go.

 

[88v8]

How are the wall plates supported? Is there a dpc under them, slate? The beam visible appears to be bang up against damp-looking brickwork?

As Matthew noted, drying out will take many months, but would not expect the timber to be actually wet.

Ivor

 

[drpepe]

Thanks for your responses guys. It sounds like it would be wise to re-assess in the Spring next year? (if/when it stops raining)

How are the wall plates supported? Is there a dpc under them, slate? The beam visible appears to be bang up against damp-looking brickwork?

As Matthew noted, drying out will take many months, but would not expect the timber to be actually wet.

Ivor

Yes there is no membrane / slate to be seen either between the wall plate and the wall, or between the joist and the wallplate - presumably the slate would not be so thin as to be difficult to determine its presence? In other rooms the wall plate is not so wet despite the pier stonework being damp, suggesting there is some kind of functioning damp protection in those parts?

Yes it is odd that the wood appears to be sopping wet - the muddy floor is slightly dampish to the touch but not overly so (it is loose and particulate) and certainly no standing water under there. Could the damp wood / stone be caused by rising damp plus no ventilation over many years? The conservatory has been blocking ventilation for around 15 years.

 

[MatthewC]

I agree it is puzzling that the wall plate is as wet as you say. Is this wall plate resting on, or otherwise in contact with, any earth? Or have you had any water actually flowing around there? If it was actually covered by earth then it needs some serious drying and it it still touches damp earth then i would suggest it will never properly dry.

I had some wood in the walls, and some was dripping wet even though the wall seemed pretty dry by then. I think it was a case that where the wall had been subject to huge amounts of water flowing down/in it, the stone and brick then dried out first. That wood was so wet that I doubted it would ever dry and so replaced it with dry bits of redundant joists where I wanted to keep it wooden, and with brick in other places. The impression I had was that rotten wood holds a lot more water than good wood and, possibly, wood preferentially attracts the water out of the brick as the brick dries. True?

 

[drpepe]

I agree it is puzzling that the wall plate is as wet as you say. Is this wall plate resting on, or otherwise in contact with, any earth? Or have you had any water actually flowing around there? If it was actually covered by earth then it needs some serious drying and it it still touches damp earth then i would suggest it will never properly dry.

I had some wood in the walls, and some was dripping wet even though the wall seemed pretty dry by then. I think it was a case that where the wall had been subject to huge amounts of water flowing down/in it, the stone and brick then dried out first. That wood was so wet that I doubted it would ever dry and so replaced it with dry bits of redundant joists where I wanted to keep it wooden, and with brick in other places. The impression I had was that rotten wood holds a lot more water than good wood and, possibly, wood preferentially attracts the water out of the brick as the brick dries. True?

My wife thinks that the wood (pictured above) has got even wetter looking since we dug the floor out and installed more airbricks... i 'm not sure about this but am willing to believe or hope that this is a manifestation of the overall drying process ...

It will probably need a whole summer for us to be sure that things are improving.

 

[drpepe]

I revealed the arch on the rear fireplace this weekend. I want to knock out all the brickwork under the arch in order to create a bigger opening as a storage area and put in ventilation of the subfloor via a floor grille.

As you might be able to see the blackened bricks on either side of the opening may have been built afterwards. the original(?) bricks seem to have been 'nibbled' away somewhat to accommodate them - best seen 12 rows up on the left hand side. Will this have weakened the structure so the bricks below the arch shouldn't be removed? Some of the bricks at the bottom (see right had side) actually just dropped out as I removed the concrete hearth...

Any ideas whether it is feasible to expect the arch and sides to be ok to support the chimney if i removed the bricks and lintel underneath it?

I guess it mightn't be a good idea to just have a go at this - or is it a DIY job?

 

[MatthewC]

Any ideas whether it is feasible to expect the arch and sides to be ok to support the chimney if i removed the bricks and lintel underneath it?

I guess it mightn't be a good idea to just have a go at this - or is it a DIY job?

I got my local self-employed builder to repair a similar sort of arch above a window. It had a soldier course of "rubbers" which had all slipped a bit and there was no way I was going to risk having the stone work above fall on me head!