plywood problems

Hi, I came across this forum when I was looking on the internet to try to find out some information on plywood. I couldn't really find any answers to my queries so wondered if someone on here maybe able to help me please? Last October I had 2 new stables and a garage built. The insides were lined with plywood. About a month or 2 after they were put up we started to have problems with damp. Initially this started as small black dots but quickly deteriorated to thick mould in various places in particular the corners and some joins between the sheets of plywood (although the black spots were appearing everywhere but the green/white mould was worst in these places). We contacted the firm who we got them from and they said they thought it was a problem with the ventilation. They have since been and sanded off the mould, put mould inhibitor on the affected walls and increased the ventilation. They also found water to be coming into the building through the window and door where we were getting mould on the joins between the plywood sheets and this is being rectified. We have arranged with the company to change the stables to sterling board and were going to leave the plywood in the garage. They are coming next month to do this. We didn't want to leave the plywood in the stables as where the water had been coming in there was also green mould behind all the plywood and we don't want to use anymore mould inhibitor in the stables. Also the black damp spots are continuing to appear despite the increased ventilation. We were happy with what we had arranged with the company but on going out today I have noticed that in various places the plywood is starting to separate. It looks like the outer part is coming away from whats underneath and the wood has ridges in it in places. Also there are pink patches appearing over the plywood and I've no idea what these are! I'm now worried about leaving the plywood in the garage and was trying to find out a little more before contacting the company. I was told they had used exterior grade plywood but from the problems I've described do you think that is the case? Could we have the above problems if it was exterior grade plywood or could it be interior grade? Does anyone have any ideas as to what else could be causing the above problems other than air circulation as I'm sure that's not the cause of the plywood separating and the pink patches appearing. I like the colour pink but not inside an outside building!! Thanks for any comments. Lucy

Greetings Lucy welcome to the Forum.

As you !, I have NO idea what that Pink is. Probably a form of mildew or mold.

I absolutely hate to use Plyboard in the manner you have. It's (interior or exterior) just too sensitive to Humidity, which is the reason it's separating IMHO.

Possibly, IF you had sealed it before you installed it (both sides), you might have gotten away with it. But, from what I can tell you're already well into the job, and pulling it off the walls may be more trouble then it's worth.

If you spray it with a Bactericide or Fungicide, you may not get to all the places needed, and it sounds like you don't want to use that stuff anyway.

I know I haven't given you an answer to the problem, but, maybe some sympathy will help.

Have a good Day !
S.W.

Hi, Thanks for your sympathy!! I looked up pink mold on the internet and found you can get a pink mold but don't know if it is that as it doesn't wipe off. I then contacted the company and they said its a filler they use in the boards. Don't know why the top of the wood is coming off to show it (and why you'd use a bright pink filler!) but its a bit of an on-going thing at the moment which we'll hopefully sort out soon! Thanks very much. Lucy