Replacing rotton sundeck/engine cover

[Robert95z]

The wood has been rotting for some time now on my 09 bayliner 185. Ive decided to go ahead and replace the wood. After removing the vinyl and foam, i found the wood to still be saturated. Also found a bunch of random wood screws??

My 2 questions are..

1. What kind of sealer do I put on the wood to prevent this from reoccuring. Ive looked at West Systems epoxy, which is really expensive, cheaper alternatives? Wood sealer you would use on a wooden outdoor deck?

2. Look at the attached picture, this material was on the underside (engine bay). Its like a cambric, but I dont know what kind of material it is or where it can be purchased, any ideas?

Thanks!!

 

[Lager]

You have a couple different options, you can either use a reg ply wood and apply a wood sealer like Thompsons. Apply it few times before you cover it.
Use marine grade plywood which already has a preservative impregnated into the wood.
Use reg plywood and slather it with some out door paint you might have laying around your house and it will still last for the next 10 years.
Wait a min, thats 3? Oh well, either way.

 

[NYBo]

A few coats of polyurethane will do the trick, plus a good cover to minimize exposure in the first place.

Use marine grade plywood which already has a preservative impregnated into the wood.

Not true. Marine plywood has waterproof glue, among other attributes that differ from the regular stuff, but it doesn't have preservative. Pressure-treated does, but is not a good idea because of the moisture content it has.

 

[Woodonglass]

Epoxy would be your best sealer but...there is an alternative that works very well. I've used it for years and can testify to it's effectiveness. You can also go online and research it yourself. If you follow the instructions and have the patience to do it properly the wood will repel water for decades. If you do a few more coats of full strength Marine varnish or 2-3 coats of Oil Based Paint to finish it off after the sealer dries it'll last for decades. This was use long before the Term Treated Plywood was ever heard of.

 

[Robert95z]

I already bought a sheet of pressure treated wood. Is that not a good idea? Should I return it for regular plywood?

 

[Woodonglass]

I personally don't like the chemicals used in the PT wood but that's just me. You're free to do as you see fit. I'd for sure let it dry for a while and then slap 2-3 coats of oil based paint on it before using it.

 

[Robert95z]

Ok so I returned the PT wood for ABX wood.

I traced my old sundeck and cutout of the new piece.

As for sealer, I decided on helmsman spar urethane.

Next, how do I accurately align all my new holes for the hinges and release/opener?

Do I use the sealer before or after I make my holes?

Thanks!!

 

[Woodonglass]

After.

 

[Chris1956]

Just so you know, I used PT plywood for my SeaRay I/O doghouse. I would let it dry well and use strips of fiberglass cloth (inside and outside) to fasten the 45 degree joints and 2X2 PT wood as reinforcing with stainless screws, for the rear and 90 degree side joints. The whole structure would be coated with poly resin, 2 coats on the edges of the plywood. The vinyl was installed over the plywood with monel staples. It was a bit lighter than the original, just as strong and lasted many years w/o any signs of rot.....