Punishment or luck?

[mattice]

Having found the source of our only damp wall in the form of an unventilated suspended floor with a 4ft space below ( the rest of the house has been concreted with the exception of this 5m x 3m section), I spent a weekend putting air bricks in, spent two further weekends with my head torch putting sister joists and vertical supporting posts in... today I went down the hole for what I vowed to be the last time, to finish the job, very pleased to find much less condensation.

As I measured up for my final supporting posts (I want to put a piano on the floor and the joist ends have suffered from wet rot), I tilted my head to one side to avoid the protruding nails from the floor above and my head torch caught a flash of white - the brickwork is absolutely covered in what appears to be cotton wool, or as I now fear dry rot mycelium.

Suddenly I have a free day whilst I contemplate next steps. We're lucky in that all of the other suspended floors have been removed and this is a relatively contained area albeit under the stairs. Next steps? Remove the lovely slate floor rip up the floor boards and joists, treat and fill in? I have a damp guarantee certificate which I suspect will be invalid, why they treated the walls and left an unventilated floor space I do not know!

If there are any words of expertise, reassurance, advice, or even a 'get a grip' it may spur me into attack mode rather my current retreat to the log burner.

- Plan of action seems to be contact the original damp treatment company and get a view on validity of guarantee - assume zero
- find a reputable firm in Worcestershire for a view (any recommendations?)
- strip out the slate - hoping to preserve
- lift the floors
- probably strip the walls (there seems to be polythene membrane from below the floor heading between the joists and the wall upwards behind the plaster
- get a firm in to treat everything
- fill in with hardcore, membrane, concrete, insulation, screed, tiles

As a side note, do you think the fresh air has brought it to the surface?

I suppose the luck part is that after today I would have sealed up my little access hole at the bottom of the stairs, and got on with life until the piano fell through the floor :lol:

 

[Lime]

Dry rot?
Hmmm, I wouldn't suspect the worse.
Can you see dry rot tendrils within the structure?
You can't miss them if they are there.

It is probably a friable white efflorescence that I would expect to come out of damp brick.
Years ago a similar substance was used in the process of making gun powder.
It is like fine cotton wool, doesn't have a structure but appears on some bricks but not others.

I'd let the drying out process do its work and not worry.
Try not to hurry things along because the drying may take a while.

 

[mattice]

Thanks for your words of reassurance and advice to slow down.

The cotton wool on the brick hasn't got any tendrils, it's very friable and I guess now that you mention it quite crystalline. I'll try to get a picture later, I hadn't fancied going down 'the hole' again, but your comments have convinced me to fit my last duct taking air to the other side of the floor space (it only has one outside wall).

When I first went down I took several pics and I've found this one which looks a little less promising. I didn't think much of it at the time as there were no other symptoms. We did have a 'damp' rotting rat smell pre-ventilation but that has gone and I put it down to mustiness.

I have to say that it's dried out a fair bit since this pic was taken. It's very local to a particularly damp corner where the gutters had been over flowing and where the new part of the house joins the old.

 

[Flyfisher]

That stuff certainly looks organic to me but I'm not knowledgeable enough to identify it, though I'm sure there's at least one person here who could.

However, I wouldn't be starting to panic just yet. From the sounds of thing, major changes have just been made to the house, gutters and downpipes have been fixed and ventilation has been substantially improved - all good things. Furthermore, spring is close and we have the summer to look forward to and all these things will combine to have a significant drying effect.

I would let the next 6-9 months do their thing and allow the house to acclimatise to its newly improved conditions before rushing into drastic action. Taking regular (monthly?) photos might also be a good idea and would help to monitor progress.

 

[DJH]

Nice looking thing though Mattice........ Glad I don't have one though.........

Doug

 

[Lime]

Yes, what is in the picture is a mould/fungus of some sort but it doesn't look like dry rot to me.

....... and don't go by the pictures available for dry rot on the web.
Almost any fungus is described as dry rot by people trying to sell their wares.

 

[mattice]

Doug - I took a picture of it a few weeks back because I liked the fractals!

I've been down the hole for the last few hours, finished putting the air duct in and propping up the joists. I'll leave for a few weeks and see how things progress.

Wow - that's a U turn if ever there was one. Thanks both. However, before I speak too soon, here's a pic of the (fingers crossed) efflorescence. Monthly photo's to follow

Thanks all.

 

[MdB]

Very much not an expert but that very much looks like Efflorescence to me.

It looks like mould but isn't. It is simply water evaporating from the surface leaving salts behind. I produced a nice crop when I removed a bath which had been leaking making the wall very wet.

Once the wall dries out (which is sounds like you are doing the right things to achieve), It will stop. Brush it off now and see if it reappears. Mine didn't.

 

[Lime]

Doug - I took a picture of it a few weeks back because I liked the fractals!

I've been down the hole for the last few hours, finished putting the air duct in and propping up the joists. I'll leave for a few weeks and see how things progress.

Wow - that's a U turn if ever there was one. Thanks both. However, before I speak too soon, here's a pic of the (fingers crossed) efflorescence. Monthly photo's to follow

Thanks all.

Perfectly harmless.

 

[mattice]

Thanks again, the subject doesn't seem half as dramatic now

 

[mattice]

Just over a month on.... I'm not sure what all the fuss was about!

The underfloor is much drier despite continued rain and saturated ground. I've spent a few weekends under the floor reinforcing the joists and all wood is now dry to touch as opposed to dripping... the 'organism' has receded! The hole we've made in the floor to fit our post to prop up the roof (the main reason we found the cellar), has a hurricane blowing through it, it's amazing how effective the air bricks have been. The piano is in place and holding!

It's given me confidence to crack on with propping up the roof. A friend sourced a couple of lovely bits of seasoned oak that he's lovingly nurtured in his living room for the last couple of months... planing, chamfering, and waxing as the grain opened up. The two posts are now in place, one above the other, propping up a very saggy purlin and broken tie beam. A day left of wedging them in, some metal work, finishing, and project one is complete.

The picture doesn't do it justice, but gives an idea!

 

[LadyArowana]

Thanks for the update, it's always good to hear how these things pan out. Very glad that all sounds successful.

 

[Flyfisher]

Hear hear. And it shows how effective ventilation can be, even at very low temperatures.