White blotches on Ipe Decking

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  • #178

    Dear All

    I have been asked by a client to resolve an issue where his Ipe decking has white blotches appearing on the surface.

    This decking was installed April 2012 and upon completion Owatrol D1 was applied as a saturating coat.

    After a party the deck appeared to have a scratch and he instructed the deck to be fully sanded down and re-coated with two further coats of Owatrol D1.

    1 month later these white marks have appeared?

    Has anyone any idea what could cause this?

    Hardydeck Outlet

    this looks like to be bleach? Have you treated it with some chemicals?

    About deckstains we have a listed the most common ones and what to do about if you find yourself with deck which is stained or bleached and how to clean it.

    Shepherds Carpentry

    Maybe a thorough treatment against mould is in order?

    From google I pulled up two links here and here that could point to the problem being a type of white mould

    The first link talks about the problem on a popular composite deck surface but the second appears to talk about it on wooden surfaces including the construction underneath.  

    Have the seen the underneath of the deck lately? Could there be a problem with ventilation underneath the deck or a nearby waste water source for the spores to take hold from?

    Good luck solving it in any case and please keep us posted

    Decking Decor

    Hi Karl

    Following communications with you and Lana and information from the client we have established the following

    Deck was realised end of June and protected with Decks Olje D1. All fine during the summer. In October a fence was add to the balcony and while being constructed the decking was scratched. Client had the deck sanded, he says by the professional, so I assume by the same people who installed the fencing since they were the people who scratched the deck, to remove the scratches and 2 applications of D1 applied. The first application of D1 being applied 2 days after it had rained, the second applied 8 days later.

    The first thing to say here is that the D1 was applied incorrectly and thus the second application has created a film on the surface as indicated by the glossy appearance. D1 should be applied wet-on-wet that is to say that as soon as the first application has gone in, you apply the next, continuing this process until the wood will accept no more oil. At this point you leave the last application approximately 20-30 minutes and then brush out or wipe up any areas of oil that are puddling on the surface and leave to dry. On a new Ipe deck I would expect 2-3 applications of D1 is all that would be needed. What should be noted is that D1’s place is in the wood not on the surface.

    From the information and photos we have, there are a number of issues here but the short answer to the blotching is, that it is water damage. So why has this blotching occurred? Under normal circumstances the drying time given for D1 is 24 hours but D1 is a naturally air drying oil and thus its drying time is affected by temperature and humidity. Low temperatures and high humidity will both slow the drying time of D1, whether each as a separate factor or a combination of both. October was a very wet month and we also had overnight frosts. What has happened in this case, is, that it has rained some time after application and the rain has been continuous or a short heavy downpour; from the photos I would say the latter is the most likely. The D1, due to the factors mentioned above was not dry enough, prior to it raining, for it to with stand a heavy downpour. As the rain hit the oil, so it broke it up causing it to dry as blotches, the larger blotches are also due to where water has sat as a puddle on the undried oil preventing it from properly drying, while the whitish appearance is due to the oil at the surface of the wood being washed away by the force of the rain leaving the wood with not enough oil in it to give the right appearance and possibly emulsification of the undried oil due to the rain hitting with force. This issue was further exasperated by the fact that the D1 had been allowed to create a film on the surface, something it is not designed to do. Creating a film of D1 on the surface will also increase its drying time especially in the moist atmosphere we had in October. The only reason these marks were not seen sooner will be due to the deck not properly drying out before then and thus not being seen.

    There are 3 choices when it comes to rectifying the situation and it will depend on the extent and severity of the damage 1- chemically strip the entire deck; 2 – chemically strip only the affected boards; 3 – sand the affected boards.

    For stripping the entire deck use Prepdeck. For stripping individual boards use Aquanett rather than Prepdeck as it has a thicker gel like consistency. This gives you more control over it, and reduces the risk of damaging good boards next to the damaged boards. With both Prepdeck and Aquanett the deck should be treated with Net-trol after stripping to restore the Ph and colour of the wood.

    For the sanding method proceed as follows. Sand the affected boards using an orbital sander and 80 grit paper. The sanding is not to strip the oil off but to sand out and blend in the affected areas. Dust off and then wipe with a cloth saturated in Methylated Spirits (denatured alcohol) to remove any sanding residue. As soon as the Meths has flashed off, a SINGLE application of D1 can be applied. This will even out the finish and bring the deck back to its original look.

    I have posted below photos of an Ipe deck where I got caught out by the weather (the weatherman said it wasn’t going to rain and it did!) using the sanding method. I hope they show you the white marking, similar to that in the photos above but just not as bad.

    Which ever option the client chooses the work should not be carried out till spring at the earliest when the weather warms up.

    On a final note, while sanding of the deck to remove the scratch marks was ok there was no need to apply 2 applications of D1. Why? While sanding the deck will remove the appearance of the oil it will not remove the oil that has penetrated in to the wood, only using a floor sander with a very coarse grit will do this. Applying 1 liberal application of D1 is all that would have been needed to restore the deck, since all you are doing is topping up the D1, which is still in the wood.

    Decking Decor

    Water Damaged-B


    lucas phillips

    @Decking decor- I have a question I hope you can answer. I have a similar light white glazing as in the photo you added (Water damage 1)
    With mine it’s a brand new Ipe deck. I oiled it and it started raining 6 hours later. I’m thinking the oil perhaps didn’t dry properly and that’s why it already looks old with a light whitish haze. Can you suggest how to rectify it? As it’s new perhaps stripping it is OTT? Would Netrol be sufficient? Or do I indeed have to strip the oil and start again? Thanks in advance

    Decking Network

    What oil did you use Lucas. Did you pre-sand or use Netrol and jet wash prior to your oil being applied.

    It may certainly be the salts in the water that has reacted with the oil. It would be wise to strip this back – try a test area with Netrol but I feel you may need Aquanett or Dilunett to strip back first (Then essential to neutralise with NetTrol). This would actually benefit if this hasn’t already been done.

    Best of Luck


    lucas phillips

    Thanks for your response Karl. I didn’t pre-sand or use Netrol. It was brand new so didn’t think you needed to treat it first before oiling it. I wouldn’t even go as far as saying it has white blotches. It just looks really dusty and a bit weathered. Maybe it’s the unabsorbed oil attracting dust. Hope you can help, cheers

    Decking Network

    My pleasure Lucas.
    When you have new hardwood theres are a few factors to consider.
    1. The hardness of the timber will reduce the oils ability to soak in, so you should use oils appropriate for hardwood.
    2. The timber will have Mill Glaze from its production. Consider a very fast spinning blade cutting the timber at high speed, it gets very hot and almost cauterises the surface.The cutters of the planer close the wood pores whilst the natural oils come to the surface of the timber through the machining heat. As the wood cools these oils produce a glaze on the surface of the wood. It is this that prevents the new oil soaking in to your timber.

    So, this is why its best to apply PrepDeck which opens up the surface of the timber and removes any surface film or oil. You then Neutralise this with NetTrol, now this then removes any staining as well as neutralising the effects of the Prep-deck. You can then let it dry and when it is, you then saturate your timber with something like Textrol or Aquadecks (my favourite).

    A good tip is to get the oil IN the timber and not ON the timber… wet on wet application and get it saturated … Best of luck

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