House wash mix caused decking sealant to peel

Hi guys, did a job on Tuesday and it appears that the water based deck sealant started to peel in places after I had washed the house, the customer is convinced it is not my fault, I offered to pay for the deck to be resealed they wouldn’t hear of it, the husband had already sanded back the parts and was reapplying sealant.

It only happened on certain sections of the deck that was in the prolonged sun exposure, mix was not directly sprayed onto the deck, mix was only 0.7-0.8% applied with a 12v pump as my DS broke last week and the new one is yet to arrive. So in this instance I know the precise ratio of the mix, dwell time was 5-10 mins and all rinsed off with one of the spray tips from the Jrod with a 4gal 4k machine.

I only found out when I arrived today to do a shower door restoration, and they informed me, they think it was because they used a different brand of sealant on the front deck where the water based sealant was , where the rear deck which had oil based sealant was not affected at all. The paint store said it would come off with pressure, however I only used soft washing tips.

I guess I am wondering if anyone else has experienced anything like this, I couldn’t find anything specific with search, what would have caused this:
Oxidization from the sun?
Did the mix strip it?
Pressure? ( didn’t use any)
Home owner applied old sealant incorrectly?
Hopefully someone will chime in and offer their expertise as I would prefer for this not be a repeatable occurrence, although it has never happened before.

I’ve never encountered this. I can’t see such a light mix peeling a sealant. Can you post some pics? I would think the sealant was not applied correctly.

First off water based sealer will not peel off . Solvent base sealer will though.

I do not have any pics, I never actually saw the issue, I was just informed. But the customer lives on ocean front, and mentioned how they liked this sealant as they didn’t have sand before applying it, maybe there was sand or salt contaminating the surface prior.

They probably applied it over another sealant.

Or they like it because it $99 at Home Depot. Some crook quoted the $2000 to do the same thing lol I run into diy sealer all the time . It’s complete crap

G’Day Steve, I’ve had 3 of those so far this year, but that’s an exception, and a couple last year.

They have all been old coatings, not badly sun damaged & both waterbased (Cabot’s Aquadeck) and oil-based (Sikkens & traditional penetrating oil).

Like you, my mix is about 0.7% bleach, but I probably do bigger sections so the deck is wet for longer. I find it’s worse where I’ve walked - especially if I have walked back & forth hand brushing the old weatherboards.

My explanation is that

  1. old coatings don’t like being wet and walked on,
  2. sometimes people don’t prepare the re-coat properly (some need sanding, but the tin is vague about it),
  3. sometimes people change product and the new doesn’t stick very well to the old.

Case 1 - Owner recoats with AquaDeck nearly every year for 15+ years, but never washes or sands
Case 2 - Owner applied traditional penetrating oil every year whether it needs it or not - last time it took a week to dry (leaving a layer of penetrating oil on the surface),
Case 3 - Painter re-applies Sikkens every year without sanding.

I’ve taken to asking more questions about the deck - product, age & recoat regime and warning the owner that if old &/or not prepared properly the coating may breakdown & lift-off.


Thanks for the reply John, what is normally the outcome?
Do they expect you to fix it?

The house That I did, the neighbors booked me in for the following week, when I saw the neighbor I did the week before he was making out like it was fully my fault, even though a few days before seemed like it was about time for a reseal.

Dont stress steve, I reckon the client is trying to put the blame on you unfairly.
From what I can gather from details given it is likely that insufficient preparation before application of sealer is the likely culprit.
If it really is bothering you drop back around to the job and ask to be shown affected areas and take some pictures. Also try to peel off a little more with your finger nail to assess if coating was still soft when you washed, it may have hardened by now.

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Hi Steve, sorry for the delay in getting back to you. I’ve only had one who was upset, the other new the deck was in need of a re-coat - I offered to inspect & examine, but they didn’t want me too, so I didn’t. Probably lost the customer, but it was quite a distance away, and I didn’t price it very well, so no drama.