dry rot & lime render

[Anonymous]

Thanks for the advice so far. I've dug the french drain and cleaned the gutters, fixed the chimney pots etc.... and now I need help with

1/ We have dry rot in patches, is there an alternative to chemicals in treating the areas infected. We would prefer not to use chemicals for the sake of our and the house's health.

2/ I'm warming to the idea of lime render to replace the concrete/cement render which is cracked ( and funnily enough on the side of the house which is damp and has the rot, no coincidence ??) what I had also thought from the outset was dry lining the interior. Would this negate the positive effects of the lime render on the outside, eg breathability, ?

Any help or advice would be greatly received

John

 

[Anonymous]

"1/ We have dry rot in patches, is there an alternative to chemicals in treating the areas infected. We would prefer not to use chemicals for the sake of our and the house's health. "

?

Real, actual, in the-the-flesh, Serpula lacrymans, dry rot? Or brown rot damaged timbers with a bit of cross-cracking?

If you have mycelium creeping across the walls, dry it out with a fan or dehumidifier. Then cut away the decayed portions of existing timbers and isolate any replacement timber from the surrounding masonry.

There's no need to use chemicals in the vast majority of situations. Decay fungi, like all fungi- strangely, can not exist without water. Sounds like you've cured the water ingress, so there's little point trying to kill something that's already dead.

As ever, a detailed description of what you've got, or photos would help the diagnosis.

Matt Green

 

[Anonymous]

I dealt with a patch of dry rot that had infested a timberframe partition wall next to a leaking shower tray. I ripped out and burned all the timber and plasterboard, then I burned off the tendrils that were climbing up some neighbouring masonry with a blowlamp. This seems to have done the trick.

 

[Anonymous]

"I ripped out and burned all the timber and plasterboard, then I burned off the tendrils that were climbing up some neighbouring masonry with a blowlamp. This seems to have done the trick. "

Yes, yes, I should think so....I mean....if you haven't got any Polaris Missiles on you at the time, certainly.

Matt Green

 

[Anonymous]

When it comes to dry rot, I don't mess about mate!

"I'll be back!"

 

[Anonymous]

Thank you so far guys,
I can confirm that it is dry rot, tendrils and stuff!
The worst of which was on the timber lintil of a doorway blocked off by two layers of brickwork, one of which was infested, now removed, the other looks ok ( about 12 inches between the two). The outer brick wall is hard against the outside render, as was the lintil which was suffering from wet rot and dry rot!
The real walls are rubble. Does this make a difference in how to treat chemical free?
I've heard a real dry rot horror story recently and wouldn't want to make a mistake.

Any suggestions for No2??

Thank you in advance

John

 

[Anonymous]

On the dry rot subject, John, my only additional comment would be - don't take chances. If there is the slightest risk that there are still dry rot spores in any area, treat it. Better safe than sorry with that bl**dy stuff.
On point 2, could you go into a bit more detail? You may have described the building in a previous post, but I can't remember the information. Do I understand that this is a stone building with a cement render on one (damp) outside wall that is cracked and needs replacing?
If that is correct, then you would definitely do the building a favour if the cement came off and a lime render went on. This would help the wall to give off its moisture.
But don't stop there. It's best to investigate more fully the reasons why the wall is damp. Does it have a dpc, and if so, has this been bridged by the rendering and/or high soil levels? Is there some problem with the guttering or the roof, etc. that might be contributing to the damp?
You might even consider digging a french drain along the base of that wall to help disperse moisture.
As to internal dry lining, this would best be done by battening the wall and then fixing your lining on to the battening, leaving an air gap behind. Be sure that you allow air to circulate freeley behind all areas of the lining by leaving plenty of vents top and bottom of the false wall structure.

 

[Anonymous]

Thanks David

3rd time lucky for this ( " file error>>>" aaaaagh

Yes, it's a rubble stone built cottage with cement/concrete render, although only the gable end in question is cracked, I will probably remove the rest if that would be advisable.
I'm about half way round with a french drain which is about 6 inches below the slate ( there is no dpc ). This was to lower the soil height, but also there used to be a summer house attached to this side of the cottage and the foundations to this were too high. The cottage is on a slope with the bad side at the top. There was also no heat on this side of the house for more than 2 years.
I had thought of battening the inside walls and putting insulation between the wall and the plasterboard but wasn't sure if this would conflict with using lime to render. Your suggestion of air vents I hadn't thought of. I take it you mean venting to the inside? and roughly how /or spacing of the vents.

Thanks again

John

 

[Anonymous]

John - all of what you have described easily explains why this wall is damp. Possible run-off water on the high side, high soil level, cement rendering, no heat for two years - it's classic stuff.
If you're going to remove the cement rendering, I suggest you try to do so before the summer, then leave the wall unrendered for a few months during the warm weather. Obviously you'll have to re-render with lime before the cold weather arrives in late autumn, but those few warm months of "naked" masonry should do wonders for drying the wall out.
If I were you, I wouldn't rush to dry line the interior of the wall. What is it currently plastered with (if at all)? If it's gypsum or cement, then hacking that off, too, would help the drying out process - even if you only hacked it off up to about 1 metre above the floor (if you can't face doing the whole thing). Then, once again, leave the masonry naked for a few months.
You mention that you are digging a french drain "6 in below the slate", but you say there's no dpc. What is this slate? If it's the edge of a slate layer in the masonry plinth of the property, then that is a dpc - slate was often used like this and is quiter effective so long as it isn't too broken up. So taking your french drain down to 6 in below this is excellent (so long as you don't go down vertically to below the full depth of the foundations).

 

[Anonymous]

David, thanks for the response.
The interior walls are a mixture of gypsum and cement, which is a pure b*****d to get off.
There would be no problem leaving the outside wall for a few months, the inside...I'm keen on making habitable, and moving on to the next room!
I take it that there is no reason not to dry line ( it gets very cold ) and it won't counteract any other measures such as lime redering? The other reason for cracking on is we want to instal a multi fuel stove, which I would imagine would help in the whole process.
I appreciate your feedback

John

 

[Anonymous]

OK Jon, I take it you won't be hacking the plaster off the inside!
You asked for more information about dry lining, relating to air circulation. The way I have seen this done in the past is to fix vertical 25mm battens (pressure treated timber) to the wall at 600mm centres. NB: don't fix any horizontal noggins - these will impair air flow. To the battens, fix foil-backed plasterboard. If you want to avoid a plaster skim at the end, use taper edge palsterboard and fill the joints the usual way. You can slip some insulation behind the plasterboard if you want to, but you must ensure there is sufficient airgap against the wall to allow air circulation. So if you intend to put in an appreciable amount of insulation you may have to thicken your battens.
When you fix the plasterboard, ensure that you leave about a 12mm gap above the floor at the bottom and below the ceiling at the top, for air flow. Then when you fit your skirting, drill a line of holes along the bottom of it to allow air to enter. At the top you can leave the 12mm gap as it is, or you can fix cornicing to the plasterboard, a little below the ceiling - this makes the gap look a bit less obvious.
I hope that helps.