Suspected dry rot

[JG]

I was hoping someone might be able to help me I am in the process of buying a c1920 end of terrace house and am experiencing a few problems. I have been told by the surveyor that we have damp on all the external walls (50% reading) which is due to the external path being laid to high a number of years ago which covered the airbricks and therefore there is no ventilation under the house.

I have had a reputable firm quote for damp treatment, reinstating airbricks and creating a French drain to prevent the problem. However the surveyor and the damp company have both expressed concern about dry rot potentially being present under the floor boards. Due to an expensive oak flooring covering up the original floorboards I know the owners are going to be very reluctant for me to get someone in to investigate further. I am however very nervous about going ahead and not knowing.

Can anyone suggest if there is any other way of identifying whether this is going to be a problem and whether I really should find out what is under the floorboards before going ahead?

Thanks in advance for your help – it is all very new to me!

 

[NT]

I guess whoever buys it will get it without really knowing You can at least obtian some amount of information as to condition by standing on tiptoes and dropping onto heels, a rotten floor structure will shake all over the place, things will roll off the table etc. Its not a foolproof method, and doesnt tell you if theres rot or not, but it will tell you if the floor structure is good and sound or wobbly.


NT

 

[Penners]

If you're unable to use your eyes to check for dry rot, the only other (rather less reliable) organ you can rely on is your nose. Dry rot gives off a mushroomy, dank sort of smell.

However, even that probably won't be much help if the under-floor cavity has been completely sealed off. The smell might not get out.

Is there any way you could dig down to one of the submerged air bricks outside and have a sniff? This is a very long shot, and probably fairly unreliable, but I can't think of any other way for you to have any chance of investigating.

It must be said that a damp, unventilated under-floor cavity is just the kind of place that dry rot likes, so I think your surveyor is right to alert you to the possibility. However, if you are keen enough on the house, then you might consider it worth the risk, and perhaps try to get a rough idea of what dry rot eradication would cost you, as a "worst case" plan.

What's the damp treatment that the reputable firm has quoted for?

 

[Matt Green]

It must be said that a damp, unventilated under-floor cavity is just the kind of place that dry rot likes,

No.

No it isn't. It's the last place it develops unless there's a leaking pipe under the floor or a downpipe discharges into it. It need fresh water to develop, not ground water. Penetrating damp doesn't bring about dry rot and a lack of ventilation under a floor is staggeringly unlikely to. Insect attack: yes, wet rots in the joist ends: yes, dry rot: no.

However the surveyor and the damp company have both expressed concern about dry rot potentially being present under the floor boards.

so I think your surveyor is right to alert you to the possibility.

Rubbish- the surveyor is covering himself because he doesn't have the faintest clue about the organism he's dealing with. The other guy is a salesman. Both are scaremongering.

If they'd have said wet rot would you have been so worried? thought not. Despite the fact that it decays wood in the same way and is a lot more likely to be there.

However, if you are keen enough on the house, then you might consider it worth the risk, and perhaps try to get a rough idea of what dry rot eradication would cost you, as a "worst case" plan.

It will cost you bits of a new floor and the cost of fixing whatever fresh water source caused the problem. Put a hatch in the floor around pipe joints and/or down pipes if you feel it's worth it.

:evil:

Matt Green
-who wonders exactly how many times he has to post/lecture/write to stop people posting erroneous rubbish about dry rot. I suppose it's not uk.diy though. They'd have likely advised you to burn the house to the ground by now lest 'spores' get in.

 

[Nemesis]

Matt - come on - stop sitting on that fence, tell us like it is!!

 

[Sal]

Matt - come on - stop sitting on that fence, tell us like it is!!

too funny!


so is dry rot not quite as scary as everyone will have you believe?

 

[Lime]

Matt - come on - stop sitting on that fence, tell us like it is!!

too funny!


so is dry rot not quite as scary as everyone will have you believe?

I lived in a house with some dry rot in the cellar. I found it within the first week of living there as I could smell it.
It looked quite pretty in a frightening sort of way. The tendrils (Rhyzomorphs) wrapped over bricks like ivy. Sometimes the humidity was so high in that area that condensation formed all over the place.

Opening a few windows and under floor vents got rid of the humidity.
I used copper sulphate solution (from a chemistry set) on the dry rot and that seemed to stop it.

 

[Nemesis]

http://www.ridoutassociates.co.uk/

I think we can believe Matt. Stop feeding it and it goes away.

 

[Penners]

JG - just so you're aware. Matt is a professional expert on this subject, so his unequivocally forthright dismissal of some of the information in my post should be treated as completely reliable.

I'll just crawl away into a corner and lick my wounds.

 

[Nemesis]

Have a stiff drink Penners. It will be better for you really, all that saliva will be messy and cause wet rot. Or not. (I wait to see what Matt says...)

We are mere mortals and so glad that Matt drops from on high from time to time to gently chide us, in his diplomatic way, and put us on the path of right.

And save a great many punters a vast amount of dosh in the process, of course. For which he deserves undying gratitude.

No doubt the timber treatment cowboys will be putting a price on his head very soon.

 

[Sal]

great to have some experts on board.

have now taken to sniffing around for mushroomy smell. prior to that was only looking for alien type growth. promise not to throw any scraps if I find one.

 

[Penners]

so glad that Matt drops from on high from time to time to gently chide us, in his diplomatic way, and put us on the path of right.

And save a great many punters a vast amount of dosh in the process, of course. For which he deserves undying gratitude.

No argument from me (with the possible exception of the word "diplomatic"!)

 

[thiambal]

I am particularly impressed that Matt has a "doctorate studying wood-boring weevils".

I love things like that, I had a friend who did a doctorate in the decline of the main battle tank, people with such depth of knowledge always make me feel slightly inadequate.

It also makes me wonder if these are the same weevils that you get in biscuits - if they are and you have a wooden leg things could get really troublesome :wink:

 

[PC]

Assuming it’s a 1902 property can I assume it has cavity walls, if so why not knock out the air bricks and inner brickwork and see if you can see through into the floor void, these can be easily replaced.

Alternatively could you use an optical Boroscope in a discreet corner of room, this may give indication of rot in supporting floor timbers, which if it exists would probably necessitate repairs of some description.

The surveyor was quite right to advise on concerns over potential decay as if there’s damp then timbers in contact could be considered at risk.

If the vendors want to sale then they will have to allow some form of investigation if not for you perhaps the next purchasher.

PC

 

[Matt Green]

The milkman usually arrives before I read the forum in the morning, occasionally he does not and I don't get a cup of tea first.

Pray that he never forgets to deliver entirely.

Seriously though, there is a lot of tosh written about what is just a very efficient brown rot decay fungus. The fact that some authors perpetuate the situation by not bothering to check their references thoroughly, certainly doesn't help either. Surveyors and treatment people who present it as a super-sentient organism that will erupt spontaneously, destroy your home, choke you with spores, suck the water from your taps and eviscerate your pet hamster do make me agitated though.

:wink:


Matt Green

 

[Penners]

Agitated? You??