Timber rot - what if you just can't remove the moisture source?

JustAnotherSaver

woodbutcher wrote: »

The air bricks are not your problem. You can add as many as you like and it won't make any difference. The ones that were fitted originally will do the job if they are clear and you have a throughdraft.

The problem is water soaking up your sleeper walls, through the old and broken down dpc and soaking into the timbers, therefore rotting them. My house is the same age and the floor was at the end of it's lifespan. It cost me a couple of hundred quid for timber, sand and cement and a couple of days upheaval. I didn't have to pay labour charges admittedly, but it shouldn't be a massive amount to sort out and sounds like it needs doing.

Perhaps worth writing off the living room for even longer then until we can get it done.

Surely that wont be the magical solution though? So we put down DPC, we do the sand & cement, perhaps wrap the ends of new tannelised joists in visqueen/similar

So basically it's as it is but with DPC between the woodwork & brickwork.

The moist air is still there due to the water level. Wont this continue to make the joists moist? I took a reading tonight in the centre of a joist which reads at 31% - high enough for decay apparently (with the figure we're apparently wanting is 20%-22%).

OR, would you expect it to last some time, perhaps our remaining lifetime there but break down once we're dead & buried?



Again though, with us having a habit of getting the wrong people out - would your standard builder in the yellow pages be the one you'd turn to for this? This isn't anything specialist? I make no apologies for asking what is probably a silly question as i'm just cheesed off totally with the whole thing & am sick of constantly making mistakes.

phill99

Woodbutcher is correct. The Stream is a red herring. Even if it wasn't there, given the age of your house moisture would still likely be present in your beams. You need to remove them, replace the DPC in support walls and main walls, replace the wall plate and replace the beam.

It's a relatively straightforward job for a bUilder.

DRP

phill99 wrote: »

Woodbutcher is correct. The Stream is a red herring. Even if it wasn't there, given the age of your house moisture would still likely be present in your beams. You need to remove them, replace the DPC in support walls and main walls, replace the wall plate and replace the beam.

It's a relatively straightforward job for a bUilder.

yes agree.

we had similar done by a builder in a knockthrough lounge diner (7mx3m) - cost us about £1700-1800 for new pier walls, joists and floor boards (boards new cut from victorian pine joists, so a bit more than new boards or chipboard).

So a decent amount but it didnt totally break the bank!

woodbutcher_2

As phil said, the stream is a red herring and the timber is soaking up the moisture like a sponge because the dpc has failed. That is why you are getting a high reading.

The only option is removal and renewal. Did the same job for my neighbour last year and it cost her about £700 if i remember rightly, which was materials and skip, with 2 days labour for me.

Not saying that is what yours will cost, because i haven't seen the job and don't know what labour charges are like where you live, but it shouldn't break the bank as it's a fairly straight forward procedure.

JustAnotherSaver

There is a chap doing an extension on a house up the street. All these houses are practically the same so as such he'll have a good idea of the layout.

I asked how much it would cost roughly to do the job & he said we'd be looking at a "good couple of grand" but could obviously cut this if we rip out the timber ourselves & get a professional to take over from there. He said approx 3-4 days if someone did the entire job.



He said he'd use moisture resistant chipboard - 22mm. I didn't think chipboard would be suitable myself? Isn't it a bit mushy? He said he'd use this mainly for the cost factor, but also because it'd be easier/quicker than installing a load of flooring slats.

What do you guys reckon to the use of moisture resistant chipboard in this instance? I've emailed a chipboard manufacturer for their take on it but they & the chap i was speaking to have reasons behind their suggestions that would benefit themselves. You guys have nothing to lose or gain out of advising me hence me asking.


Also, there is still the option of leaving it & see how we get on. For all anyone knows the floor could last 5 minutes, 5 days, 5 months, years, 25 years, whatever.

So on that note, if we get the walls treated (as in plaster knocked off, started again, damp injection, tanking, re-plastering etc) while leaving the floor & get the floor done at a LATER date, would there be any negative effect in this case that you can think of? I can't but then i don't know what i'm on about

woodbutcher_2

Chipboard flooring is perfectly good and is what i use. The water resistant type is known as V313.

The floor problems shouldn't be linked to any dampness in the walls as it should have a seperate DPC built in, but if it were me, i would get the floor done and take it from there, unless you can get it all done at the same time. A couple of grand and 3-4 days sounds excessive to me, even more so if you are doing the removal of the old floor, but i haven't seen the job, so i'm guessing.

I've done a few and unless they are a particulary large room, then one day to clear out the old stuff and re-bed wallplates and one day to fit new rafters and flooring is the norm. New skirtings and any other bits could take it to 3 days at a push.

JustAnotherSaver

woodbutcher wrote: »

Chipboard flooring is perfectly good and is what i use. The water resistant type is known as V313.

Really? I thought it all was? The flooring we stock is all called V313 AFAIK & we stock 'standard' 18mm, 22mm, safedek, moisture resistant, weathershield. Though i think Safedek was perhaps the old stock.

Anyway, our old supplier was Sonae who got shut down. Our supplier now is Kronospan. I emailed them & they didn't think it was suitable. I'll quote them at the end of my post.

The floor problems shouldn't be linked to any dampness in the walls as it should have a seperate DPC built in, but if it were me, i would get the floor done and take it from there, unless you can get it all done at the same time.

I don't think our budget will allow for it all at once. Delaying the living room until we can afford it all at once is an option but then as i say - the floor could last 20+ years & so we'd have spent this money for (in a way) nothing.

The wall issues are from the moist air the independent damp surveyor told us. You can see the dark line which i assume was from before a sump pump was installed. This would be the old water level i am guessing. As such it probably ended up raising OVER the DPC level. It'll have one (DPC) but i can't spot it.

A couple of grand and 3-4 days sounds excessive to me, even more so if you are doing the removal of the old floor, but i haven't seen the job, so i'm guessing.

I'm no expert but i agree. I was thinking 2-3 days. It depends though. If the workers are brew-every-5-mins workers then it'll take a while. If they're the type to get stuck in & start on time then i'm sure that can be ripped out within a day.

New skirtings and any other bits could take it to 3 days at a push.

Ahhh you make a very good point - there's a negative of doing the walls & not the floor (or floor later) - the skirting could perhaps get in the way or issues with lining the floor up & the skirting being a problem perhaps.


Anyway, the response from Kronospan:

Good morning

I am replying to your enquiry regarding the use of a Chipboard floor on top of the waterway.

I would have to say that in this instance I would not recommend the use of MR grade Chipboard as it seems that the high moisture levels are a constant in the area where they are to be fitted.

This grade of Chipboard is not designed to be used in this type of environment.

It is difficult to make any recommendations for this particular situation but WPB Plywood may possibly be an option.

This is not a product that we produce here so I cannot give you any technical details for this material.

I would also suggest you make contact with the following organisation to see if they can make any recommendations.

Wood Panel Industry Federation

Just to note: i took a moisture reading of both sides of the current floorboards. Top side was 19/20% but the underside was 26% - enough for decay (apparently).

However, they say they struggle to recommend anything. Well, floorboards have been there & i'm guessing they're the original ones which if so, have served perfectly well for 80 years.

JustAnotherSaver

In addition to the above, have any of you worked with boron?

I can't find the damp report that mentions its use but i'm sure it stated something about it treating damp. I wonder if it'd be worth getting something in to treat the joist ends.

27col

If you have a large drop below the floor boards no amount of extra air bricks will help the air circulation. I had this problem in my first house and it was solved be infilling the underfloor void to just below the floor joists. This will create a far superior air flow instead of the stagnant "pool" of air that you have at present