Dry Rot Help!

[Emotionalrollercoaster]

Having a bit of a panic. I'm steadily trying to work through renovating my 1929 semi-detached house in Derby. It's had an injected DPC around 25 years ago.

I started on my utility room yesterday, and found what I think is dry rot in the skirting, with some rotten window framing. It was tiled to halfway up the wall, and all of the lime plaster was blown. It's been skimmed with gypsum at the bottom, presumably when the DPC was added.

Pictures of the affected skirting are attached (no more pictures as the skirting board has now been disposed of) and I've marked on the pictures the area underneath. The wood felt dry to touch with stranding fungus underneath. The walls feel cold and slightly damp but no really wet areas.

Obviously a bit of googling has made me panic (it's the first house I've owned and it's a bit of a tough time at the moment anyway).

Outside, there's a concrete paver path that abuts the house and patio along the other external edge, with a very damp area under the back doorstep.

Gutters look in ok condition but going to get them checked and cleaned this week.

I'm just not sure what to do next.

1) How far do I need to go looking for other areas of dry rot? Kitchen has boards and backs of cupboards smell damp.

2) I suspect I need to get a French drain or similar along the edges of the house - am I on the right track and how do I go about doing this?

3) Do I need to get someone in to treat the dry rot, and if so, who? I'm on my own so don't want to get taken for a ride and finances are tight.

 

[Emotionalrollercoaster]

Couldn't attach all photos. The external photos are attached here....

 

[a twig]

Firstly, don't panic, almost all of us on here have had to deal with damp. Do not let yourself get conned into the snake oil damp contractors with their magic creams and injections. Almost all fixes are usually DIY-able.
Checking rainwater goods is an excellent first step, make sure they are all clear, and the gullies that the downpipes go into do actually drain away. Resolve any issues you find, and then start trying to dry the house out (heating, de-humidifiers etc) - if that solves the problem then job done.
If it doesn't seem to be improving after a few weeks then look for other causes, high ground levels, non-breathable finishes etc might all be part of the issue. I suspect behind that half height plaster you might find tanking, which won't be doing you any favours at all.

 

[stuart45]

All of the above, plus on cavity walls, debris at the base of the wall in the cavity can cause damp issues. The wall could do with a lime mortar repoint. It also looks to have been painted at some point in the past.

 

[Toby Newell]

+1 to both of the above, there is a damp expert on here, hopefully he chimes in.

1) How far do I need to go looking for other areas of dry rot? Kitchen has boards and backs of cupboards smell damp.

You need to get an honest damp expert in, unfortunately there are many disreputable types in and around the industry.

2) I suspect I need to get a French drain or similar along the edges of the house - am I on the right track and how do I go about doing this?

Again the damp expert should advise.

3) Do I need to get someone in to treat the dry rot, and if so, who? I'm on my own so don't want to get taken for a ride and finances are tight.

Yes. You DO have dry rot, the operatives may need to remove more structure to check how far it goes.

Fungi is amazing stuff.

The spores (think: seeds) propogating is the first stage.

The white hair-like strings (hyphae) are the second stage stage, (think: sproutling) looks like you have the start of the third stage (mycelium) this is when the hyphae consolidate, get thicker and spread, carrying nutrients (think: roots) Mycelium form the bulk of the organism and can spread, like roots, far from the source, you need to remove all the mycelium or it might spread further.

I would not panic but you are right to be concerned. Mycelium spread in a contiguous manner.

What you don't want to see is the fourth (last) stage, this is when conditions are favourable enough (mycelium has enough nutrients) that the mycelium can grow fruiting bodies (think: fruit) ie 'mushrooms' this fruit then releases millions of tiny spores (think: seeds) than can spread far and wide over the whole structure.

Dry rot fruiting bodies are mustard / ginger colour surrounded by yellow and purple metabolites and look like flat mushrooms, if you see a lot of yellow staining this means the mycelium is vigorous.

The area shown doesn't look terrible but it is important to get it sorted asap. It's called 'dry rot' because the fungus can live off the natural level of moisture in the timber, so even if you solve any damp issues the dry rot can continue to grow, and degrade your structure (although it may be slower to spread to other areas as the spores initially need (20%RH) damp timber to 'germinate'.)

FYI timber in a 'toasty' modern home may be 4-6%RH, more typically 8-12% RH, timber in an old slightly damp property will be in the range 10-18%RH, anything above 18-20% you risk rot (wet or dry) especially if the moisture level is constant.

Ideally, to be safe, you would want to maintain moisture levels <16%.

Again, I am not a damp expert but have advised many clients on damp issues which have been corroborated by subsequent surveyors.

Sorry to hear of your issues and best of luck.

 

[Toby Newell]

I can add, I would remove all woodwork from that room adjacent to that wall, including any the other side, check the floor boards if you have them (on the adjacent side) I would also remove the bottom quarter of the plaster to check underneath.

Remove the paint on the bricks outside.

Looks like there may have been an injected dpc treatment although you dont know how good this is, possibly a good idea removing the pavers, assuming there was an original dpc when the house was built and assuming the injected one may not be 100% efficient removing the pavers would stop (possible) bridging of the original dpc. Look at your air bricks, there looks like a 20mm gap to the ground level, this is ok if it falls away from the wall, if the ground is flat or falls towards the wall then they should be minimum 75mm above ground level.

Check when you get a torrential downpour that water is not entering the airbricks.

As regards the dry rot, from an untrained amateurs point of view, from what I have seen over the years on a scale of 1 to 10 where 1 is meh and 10 is headless chicken time yours looks like a 3 - 3.5, I normally only start to get worried when I see a lot of yellow staining.

 

[Emotionalrollercoaster]

Thank you everyone! I'm searching for a helpful damp expert but it's difficult. If anyone knows someone I can trust in the East Midlands I'd be grateful.

I've looked in the airbricks with an inspection camera and just saw the underneath of my kitchen cupboards so safe to say I'm not getting a good look at the horrors under the floor.

I've increased my thermostat, drilled holes in the plinths in my kitchen and pulled back some of the vinyl floor in an attempt to do what I can to improve ventilation.

I can add, I would remove all woodwork from that room adjacent to that wall, including any the other side, check the floor boards if you have them (on the adjacent side) I would also remove the bottom quarter of the plaster to check underneath.

Unfortunately this is difficult - there are kitchen units on the other side so without ripping out the whole kitchen it might be tricky!

As regards the dry rot, from an untrained amateurs point of view, from what I have seen over the years on a scale of 1 to 10 where 1 is meh and 10 is headless chicken time yours looks like a 3 - 3.5, I normally only start to get worried when I see a lot of yellow staining.

A 3-3.5 is reassuring. I'm really trying not to catastrophise, but frankly it's been the sh***est of years in every imaginable way and it really wouldn't surprise me if the house fell down around my ears at this precise moment.

 

[Toby Newell]

Thank you everyone! I'm searching for a helpful damp expert but it's difficult. If anyone knows someone I can trust in the East Midlands I'd be grateful.

I've looked in the airbricks with an inspection camera and just saw the underneath of my kitchen cupboards so safe to say I'm not getting a good look at the horrors under the floor.

I've increased my thermostat, drilled holes in the plinths in my kitchen and pulled back some of the vinyl floor in an attempt to do what I can to improve ventilation.


Unfortunately this is difficult - there are kitchen units on the other side so without ripping out the whole kitchen it might be tricky!


A 3-3.5 is reassuring. I'm really trying not to catastrophise, but frankly it's been the sh***est of years in every imaginable way and it really wouldn't surprise me if the house fell down around my ears at this precise moment.

Check under any adjacent floors and in any cellar, if you solve any damp issues this will slow down the dry rot, just remove any damaged wood and remove any 0.5 to 1m away depending on how bad it is. Unless you find a lot of rotted wood that crumbles, lots of yellow staining and fruiting bodies it will probably be ok.

 

[Toby Newell]

Thank you everyone! I'm searching for a helpful damp expert but it's difficult. If anyone knows someone I can trust in the East Midlands I'd be grateful.

I've looked in the airbricks with an inspection camera and just saw the underneath of my kitchen cupboards so safe to say I'm not getting a good look at the horrors under the floor.

I've increased my thermostat, drilled holes in the plinths in my kitchen and pulled back some of the vinyl floor in an attempt to do what I can to improve ventilation.


Unfortunately this is difficult - there are kitchen units on the other side so without ripping out the whole kitchen it might be tricky!


A 3-3.5 is reassuring. I'm really trying not to catastrophise, but frankly it's been the sh***est of years in every imaginable way and it really wouldn't surprise me if the house fell down around my ears at this precise moment.

A dehumidifier is a good idea and to keep it heated but medium and long term you need to improve areas such as drainage / ground level / ventillation as well.

 

[Toby Newell]

You should remove some of the plaster above where the rotted skirting was, dry rot mycellium can survive in the brick work from which they get minerals, they won't be able to grow far without the cellulose sugars from wood, but if you put new skirting back without removing all the mycellium, it may rot again.

I would chip some off, brush off, apply some spray bleach, then dry out before replastering.

99% of the time I don't see live dry rot, just the dry rotted wood after it has died, it actually has to be very damp for dry rot to spread far. You are making progress, heating the property and getting humidifier in are your best short term options.

When its raining heavily go outside and note any pooling water, especially near your low airbrick, also look up to the gutters and note any leaks or cascading water that wets the masonary.

Removing those pavers that have raised the ground level is another easy win as is removing the paint from the bricks.

A lot of small actions can add up to having a large compound positive effect.

 

[Emotionalrollercoaster]

You should remove some of the plaster above where the rotted skirting was, dry rot mycellium can survive in the brick work from which they get minerals, they won't be able to grow far without the cellulose sugars from wood, but if you put new skirting back without removing all the mycellium, it may rot again.

I would chip some off, brush off, apply some spray bleach, then dry out before replastering.

99% of the time I don't see live dry rot, just the dry rotted wood after it has died, it actually has to be very damp for dry rot to spread far. You are making progress, heating the property and getting humidifier in are your best short term options.

When its raining heavily go outside and note any pooling water, especially near your low airbrick, also look up to the gutters and note any leaks or cascading water that wets the masonary.

Removing those pavers that have raised the ground level is another easy win as is removing the paint from the bricks.

A lot of small actions can add up to having a large compound positive effect.

Thank you - everything else you've said was kind of in my mental to do list so sounds like I'm on the right track. Bit of work that I didn't need right now but there we are I suppose.

Just trying to find someone to do the groundworks outside - I think getting some drainage in is key to solving it but pulling the slabs up sounds like it might be a temporary fix.

 

[Toby Newell]

Thank you - everything else you've said was kind of in my mental to do list so sounds like I'm on the right track. Bit of work that I didn't need right now but there we are I suppose.

Just trying to find someone to do the groundworks outside - I think getting some drainage in is key to solving it but pulling the slabs up sounds like it might be a temporary fix.

The slabs are too high, almost 100% they aren't helping. Building regs are airbrick to ground min 75mm unless there is steep fall (slope) away. Also paint seems helpful, but if water getting in below then paint just retards evaporation. These are cheap super easy fixes as isheating and dehumidifier.

Really good idea to go out when it is bucketing down and check for guttering / drainage issues. Gutters might have leak or need cleaning.

Only after this consider digging out and putting gravel next to wall (French drain)

Any "damp expert" that suggests a waterproof coating or dpc injection before suggestingall the basics should be treated with caution.

 

[Emotionalrollercoaster]

No obvious gutter problems but getting them cleaned/checked next week anyway.

Going to lift the slabs but it's concrete down the side with the biggest issues.

Heating is on (with windows open a crack) and getting a dehumidifier this week.

There's a cupboard under my stairs adjacent to the problem wall that I'll examine this week. It's wallpapered at the moment so going to pull that off and see what horrors lie beneath....

 

[Emotionalrollercoaster]

And don't worry - no "damp expert" is going near it with a dpc or waterproofing!

 

[Toby Newell]

No obvious gutter problems but getting them cleaned/checked next week anyway.

Going to lift the slabs but it's concrete down the side with the biggest issues.

Heating is on (with windows open a crack) and getting a dehumidifier this week.

There's a cupboard under my stairs adjacent to the problem wall that I'll examine this week. It's wallpapered at the moment so going to pull that off and see what horrors lie beneath....

All good stuff, I am sure you will solve it, hopefully the concrete comes out easily, concrete is a bit like the tardis if youve never done it before, even a small section can be several hundred kilos and 30 rubble bags. Deffo rip everything out of cupboard esp lift any floor boards asap, I amsure you will solve it.

 

[Matt Green]

Morning,

Apologies for only just having seen this (my life is bed bugs at the moment).

I don't think it is Dry Rot (Serpula lacrymans), the mycelium looks too white. Given the colour and shape of the fan, I suggest it is Mine Rot (Antrodia (Fibroporia) vaillantii). It's still a brown rot decay fungus and the advice so far remains sound. It decays timber in ground contact (hence the name) and has a higher than usual water-logging tolerance which is where you tend to find it over Cellar Rot, which is more common.

Deal with the ground water source by whatever means necessary and isolate any timbers in contact with the floors and walls in that area with a DPM or similar when reinstating and you should be fine.


Matt

 

[Toby Newell]

^^^^ defer to this man, he is an expert.

 

[William]

Years ago, I bought an Edwardian house with a serious dose of dry rot and while I wouldn’t wish to venture any positive ID of the specific fungus, I remember that apart from visible mycelium, the dry rot fungus tended to create shrinkage in infested timber with a characteristic square cracking pattern and the whole area had a characteristic smell too. From photos, it might be worth looking at the pointing and the injected dpc as potential moisture sources.

How far you need to go will depend entirely on the extent of the evidence, which can only be established by stripping out infested timber and removing surrounding plaster. Hope that doesn’t include your kitchen. The wretched stuff can send out mycelia for several metres in search of a new home to produce new fruiting body, from which it spreads even further with new vigour. It can grow between brickwork and plaster and even through microscopic spaces in bricks and mortar.

Luckily I ended up with decent contractors. Probably the main reason was that dry rot had been identified at survey and I had a large mortgage retention, conditional upon having it sorted out by a firm which was acceptable to the building soc, all guaranteed for I think it was 10 years and all signed off by the building soc’s surveyor.

They also had to rectify source of moisture which was a balcony over the front door and continue removing timber and plaster for a certain distance beyond the last evidence. I can’t remember exactly but I think it was in the region of 1m, maybe a bit more. It was horrendous, with first floor joists cut out from the wall and the remaining floor hanging in mid air, supported on acros. It travelled from ground floor to first floor joists, boards, and bay window frame. Almost everything had to be cut out and replaced along nearly the entire front elevation of the property, on ground and 1st floor. They then torched the masonry and drilled holes every half metre or so (maybe even it bit less?) into which fungicide was injected to drench the wall and remaining timber. Hellova mess, large bill but no further issues.

If you need to pay for lasting remedial work, ‘suggest plenty of research and proceeding with caution ‘cos there seem to be no shortage of M. Mouse so-called professionals, contractors, masterful associations, worthless warranties and firms who might not even be around next year. You mentioned limited finances so I hope yours’ isn’t too serious ‘cos it shouldn’t be left but it sounds like you know that. Good luck.

 

[Emotionalrollercoaster]

Thank you so much @Toby Newell @Matt Green and @William - you've been so helpful and I really appreciate your time in answering my queries.

I think I've found the issue, and looks like the fungus (reassured that it might not be dry rot even if it is something nasty for wood) hasn't spread too far! I haven't found any more rotten timber so far, even in the dampest patches.

I think the issue is the pointing under my back doorstep:

Water ingress to the side of the door affected by the fungus, but also to the other side of the back door under some (very modern) floorboards in my under stairs cupboard.

Any advice on how I might sort it? I've attached some photos of what I think is the problem. It's just very close to the ground so I'm worried about how well it will dry once repointed.

 

[Toby Newell]

Thank you so much @Toby Newell @Matt Green and @William - you've been so helpful and I really appreciate your time in answering my queries.

I think I've found the issue, and looks like the fungus (reassured that it might not be dry rot even if it is something nasty for wood) hasn't spread too far! I haven't found any more rotten timber so far, even in the dampest patches.

I think the issue is the pointing under my back doorstep:

Water ingress to the side of the door affected by the fungus, but also to the other side of the back door under some (very modern) floorboards in my under stairs cupboard.

Any advice on how I might sort it? I've attached some photos of what I think is the problem. It's just very close to the ground so I'm worried about how well it will dry once repointed.

View attachment 11873

View attachment 11874

Im not an expert but I think you may need to reduce the concrete ground level, it might be bridging the dpc. I remember the airbrick was barely above ground.