Treating pressure treated wood

[ozzpoz]

Hi. In after some advise please. We recently had a summerhouse installed, just in time for winter .. it was installed on a wet September afternoon, the inside was very damp to the touch, it's finally drying out except the ceiling which is still getting condensation on it. We're airing it out as much as possible but the weather ain't helping. And mould has started to appear. I've been wiping it off daily. But the humidity is winning. I'll add a pic of what's happening. It's completely empty at the moment and I'm wondering if I should paint it or treat it with something now to make it easier to clean and maybe stop the mould getting worse. I don't want it to ruin before it's seen a summer. I'll do the exterior next year when the weather is better. So I'm just wondering if it's worth doing the interior now and what would be best to use. We want to keep the natural colour. Thanks.

 

[ozzpoz]

So that drew a blank .. has no one any ideas on what's best to use to clean that off and what would be the best product for a natural finish on the interior walls an floor. I've read that because it's pressure treated I have to be careful with what I use. Thanks.

 

[Awac]

https://www.harrodhorticultural.com...html?Aff=GPL&gclid=CLfQg7qNi9ICFYoaGwodWlkLzg
UK agent, also look on Amazon.

https://ecowoodtreatment.com/
Canadian Manufacturer, look on the web site for a video showing you how easy this stuff is to apply. Really I love this stuff, it works and you do it once. Oh, and it is cheap and eco, not something you normally see in the same sentence!

 

[Sandyn]

I'm surprised you haven't had any replies, there are many people who could give you good advice. Looks like the wood is already treated?

I would suggest that the wood used might have been well saturated for some time. I would get something sharp and poke around the wood just in case they have used rubbish wood which has already started to soften. I have had treated wood delivered and it was rotten inside. You need to dry the place out, dry heat (electric) and a dehumidifier, perhaps hire a commercial dehumidifier, the type used after flooding.

That should be just surface mould, but poke the area to be sure. I wouldn't treat the mould with anything when wet and when it dries, the wood is already treated. It's cosmetic at the moment. I would just rub it off, You could use a bleach solution, but it will go when the wood dries out and should disappear. Don't worry about long term the rot staying in the wood or anything like that, once it dries out it will be OK.
There may be some shrinkage of the wood as it dries out.
Is there a damp proof membrane under the flooring? you may end up trying to dry out the earth!

 

[ozzpoz]

I'm surprised you haven't had any replies, there are many people who could give you good advice. Looks like the wood is already treated?

I would suggest that the wood used might have been well saturated for some time. I would get something sharp and poke around the wood just in case they have used rubbish wood which has already started to soften. I have had treated wood delivered and it was rotten inside. You need to dry the place out, dry heat (electric) and a dehumidifier, perhaps hire a commercial dehumidifier, the type used after flooding.

That should be just surface mould, but poke the area to be sure. I wouldn't treat the mould with anything when wet and when it dries, the wood is already treated. It's cosmetic at the moment. I would just rub it off, You could use a bleach solution, but it will go when the wood dries out and should disappear. Don't worry about long term the rot staying in the wood or anything like that, once it dries out it will be OK.
There may be some shrinkage of the wood as it dries out.
Is there a damp proof membrane under the flooring? you may end up trying to dry out the earth!

Hi, thanks for the reply. The timber seems solid and good quality. Hopefully anyway. It was made to order by a local company rather than buying off the shelf. So we paid a premium . It is pressure treated which they did say would take a few month to dry out, it was also a very wet day when it was installed. And it's pretty much been raining ever since .. they have assured us that it's just on the surface and down to the humidity, it pretty much just blows off so I've just been wiping it with a weak mix of hot water and washing up liquid as I didn't want to damage the timber.
There is no damp proof under the floor. It's sat on bearers on top of a 6" thick concrete slab of which about 4" is above ground level. I've looked under and the slab stays dry even after heavy rain.

The walls and floor seem to be much dryer now they are a much lighter colour than when it was installed and dry to the touch, the ceiling seems to be the worst, still dark and feels wet. . I've been airing it out and have a moisture trap in there and it should have electric in there early January so I can get the heater or dehumidifier on then..

I'm wondering if anyone has used a product called OSMO wood oil. Reviews seem good, it's expensive, so maybe it's overkill. and I'm not sure if it's the correct thing to use on the inside. So many options and conflicting advice online. Solvent or water based. Paint , wax , varnish. Leave it a year, do it straight away .. any advise appreciated.

 

[ozzpoz]

https://www.harrodhorticultural.com...html?Aff=GPL&gclid=CLfQg7qNi9ICFYoaGwodWlkLzg
UK agent, also look on Amazon.

https://ecowoodtreatment.com/
Canadian Manufacturer, look on the web site for a video showing you how easy this stuff is to apply. Really I love this stuff, it works and you do it once. Oh, and it is cheap and eco, not something you normally see in the same sentence!

Thank you. I've not seen this product before but I will definitely look into it.

 

[gmgmgm]

Hi Ozzpoz, I just saw this.

Osmo is a good finish and something I reach for as my "default" finish, but I think you need to dry it all out first. I would continue to ventilate until it's bone dry inside.

A big fan, running on dry days with the door open, should get the excess moisture down quite fast. You said you were airing it, but are you using a fan to really get the air moving? It's amazing how fast the wood surface dries, when there is a fan blowing air across it.

 

[ozzpoz]

Hi Ozzpoz, I just saw this.

Osmo is a good finish and something I reach for as my "default" finish, but I think you need to dry it all out first. I would continue to ventilate until it's bone dry inside.

A big fan, running on dry days with the door open, should get the excess moisture down quite fast. You said you were airing it, but are you using a fan to really get the air moving? It's amazing how fast the wood surface dries, when there is a fan blowing air across it.

Im a bit stuck at the moment as there is no Lecky in there. It's being hooked up after Xmas. I was going to run my dehumidifier but I'd have to have the door or window open to run an extension. I also have a heater. But that's the same. Not much point with the door open. But a fan I can do. I'll get one hooked up over the weekend.
And the osmo would be ok for the inside. I was concerned as it's solvent based. Thanks.

 

[Nelly111s]

Osmo make many products, but from memory, none of them are for application on wet wood. However, their customer support is excellent. I'd suggest going on their website and sending them an enquiry.
Wood finishes Direct are also very good and helpful.

 

[ozzpoz]

Osmo make many products, but from memory, none of them are for application on wet wood. However, their customer support is excellent. I'd suggest going on their website and sending them an enquiry.
Wood finishes Direct are also very good and helpful.

No , sorry you misunderstood. I definitely will wait till the wood is dry before applying any finish. And I'll do the exterior in the summer. I'm just looking for advise on what would be best to use inside when it's dried to protect the timber , and also make it easier to clean, spills, muddy footprints ect. And hopefully if it gets a bit damp again stop anymore mould growth.

 

[--Tom--]

What do you want the osmo to do? It’s a good finish for internal wood, and wooden floors but wouldn’t paint a shed with it.

Once it’s dry you may want to consider painting the inside with pain to brighten it up if the plan is to use it like an outdoor room. If it isn’t leaking and is raised off the ground then it should continue drying as long as it’s ventilated.

 

[ozzpoz]

What do you want the osmo to do? It’s a good finish for internal wood, and wooden floors but wouldn’t paint a shed with it.

Once it’s dry you may want to consider painting the inside with pain to brighten it up if the plan is to use it like an outdoor room. If it isn’t leaking and is raised off the ground then it should continue drying as long as it’s ventilated.

Hi Tom. Thanks for reply. Ideally I'd just like to protect the inside timber from being damaged , and keep it looking nice. We'd like to keep the natural colour of the wood and be able to clean any mess up easily. Also if it does get a bit damp for any reason a mould protection. We've not had a summer house before and I know it's because of the humidity in there at the moment due to the wood being wet but we don't want to go through everything getting covered in mould every winter. Thanks.

 

[Awac]

"Eco Wood Treatment works by penetrating wood fibres to create a natural buffer against water and fungal decay. It increases wood's durability while creating an aged, silvery patina after just a few hours".

You need to mix it with water, so if your shed is wet, does not matter. Ok over pressure treated, only have to apply once, never peels, cracks or flakes off. Ages wood wonderfully. Honestly, I love the stuff. £20 well spent.
Good luck. Post a pic whatever you do!

 

[TheUnicorn]

"Eco Wood Treatment works by penetrating wood fibres to create a natural buffer against water and fungal decay. It increases wood's durability while creating an aged, silvery patina after just a few hours".

You need to mix it with water, so if your shed is wet, does not matter. Ok over pressure treated, only have to apply once, never peels, cracks or flakes off. Ages wood wonderfully. Honestly, I love the stuff. £20 well spent.
Good luck. Post a pic whatever you do!

surely, even it is water based, it will not be drawn into the wood if the wood is already saturated? it is like mopping up water with a wet sponge?

 

[Awac]

How wet are we talking? Should you use the word saturated? I have used it on wet window frames and it worked. It dilutes with water so if it was that wet maybe dilute slightly less for a stronger mixture? Honestly it is wonderful stuff. £20? Worth trying for yourself.

 

[Nelly111s]

No , sorry you misunderstood. I definitely will wait till the wood is dry before applying any finish. And I'll do the exterior in the summer. I'm just looking for advise on what would be best to use inside when it's dried to protect the timber , and also make it easier to clean, spills, muddy footprints ect. And hopefully if it gets a bit damp again stop anymore mould growth.

My advice is the same - get in touch with Osmo Uk via their website. They make loads of products and will advice on the best one. Just saying “ use Osmo” is like saying “buy a Ford car”. I have at least 5 of their products for different applications and have sought their advice on more than one occasion. The manufacturer will be as helpful as anyone on this forum in pointing you to the right product of theirs.

 

[ozzpoz]

My advice is the same - get in touch with Osmo Uk via their website. They make loads of products and will advice on the best one. Just saying “ use Osmo” is like saying “buy a Ford car”. I have at least 5 of their products for different applications and have sought their advice on more than one occasion. The manufacturer will be as helpful as anyone on this forum in pointing you to the right product of theirs.

Thank you. I did take your advise and contacted them , they said to use the 420 or the polyx 3044. We have a local supplier so I went there today. I was worried about it being solvent based and if the smell would linger for a long time. He couldnt offer any advise other than maybe use sadolin, have you ever used there products. I must admit. I'm probably over thinking it. And should just get on with it. The internet throws up so much info. Between it being breathable, solvent / water based. Oil , wax I just don't want to get it wrong. The only dead certain I've been told is as it's single skinned treat it as exterior , and don't use varnish or paint.

 

[Nelly111s]

I’ve not used Sadolin stuff, but also I’ve never found the smell from Osmo to be an issue either. JFDI !