Hi. I’m painting an exterior porch floor and need to know if it is absolutelu necessary to prime and paint the underside. The underside is also exposed. The floor is made of 1″ thick Doug fir, each one half-lapped to the next one and each lap joint is gorrila glued (i need the underside below the porch to be dry because things get stored under there). I am planning on using Zinsser Cover Stain (an oil based primer sealer) to prime and I will be using 3 coats of latex based finish on top of that. (although I’m considering using Benj Moore Urethane based paint or epoxy based porch floor paint haven’t decided yet I keep getting conflicting recipes from everyone I talk to about this). I’m planning on dipping each end of the floor boards in the primer sealer. first and each lap joint will also be primed and painted before glueing.
Wouldn’t it be better to just leave the underside as bare wood just to let it breath if it should ever get wet/ damp?
By the way, the guy in the Benj Moore paint store said that I shouldn’t use a primer sealer if I’m going to use his product. He suggested that I mix a batch of 1 part thinner to 10 parts Benj Moore Porch floor paint to act as the primer sealer, then finish paint over top of that with full strength porch floor paint. He said that his paint won’t stick as well if I used the primer sealer.
Replies
IMO the best deck finishing product is Sikkens Rubbol DEK if you want to stain it. If you want to paint it, use an epoxy alkyd floor paint directly on the wood, and sand it for safety before it dries (I mean, sprinkle anti-skid sand on it while the paint is wet). I assume the boards are KD or AD. If they're green, wait till August 2005 then paint/stain them.
Sealing the ends is a good idea. Sealing the under surface will prevent some expansion/contraction and will help reduce cracking in this massive glued-up board you are planning on constructing. I don't think you'll prevent all cracking no matter what you do, however.
If you really want to create dry storage under that deck, you'd be better off laying an exterior plywood subfloor, with a 1" to 10" slope for drainage, and then sheath that with a top-quality ice-and-snow roofing membrane. Then lay sleepers on that and lay a deck on the sleepers with normal deck board spacing. Don't forget to bore weepholes in the rim sleeper. You'll probably want to hang a false fascia on spacers to hide the rim sleeper from view, so make sure you lay your edge deck board far enough out so it covers the fascia and the spacer blocks.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
glue ing them togehter sounds like a disaster waiting to happen, they need to move independantly of each other.
Latex on a porch floor? Not me.
go with the layered approach or tongue and groove, no glue. Use a bead of a flexible, paintable sealant like Lexel in the T&Gs to seal the joint..most of the porch flooring here in the south is SYP and that works well, it is a tite joint.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
I spent the day today tearing off a deck that was painted t&g fir directly over ice and water shield. Five years old and rotting.
I have used Gorilla glue in the grooves fro smaller porches and ladings with good results but the lexel sounds like an even better way to go. It would accept some movement.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I spent the day today tearing off a deck that was painted t&g fir directly over ice and water shield. Five years old and rotting.
That just sounds like a disaster..
I'd still not glue, can't justfy the expense..besides the other points..I'm cheap. <G>
View Image
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
Hi, I'm new and resurrecting this link for more information: we have a 100 year old house that we are in the midst of repainting ourselves. For the house itself, we have been bleaching, sanding down to get rid of old paint, caulking as needed, putting a wood permanizer on, then a layer of exterior/stain blocking Kilz, and finally the paint.
For the old tongue in groove porch floors, how far "down" do you go when you're repainting them? Sorry but this is our 1st old beauty, so we're learning literally from the ground floor up!
We've already bleached the surface. Now do I sand down to new wood or just get rid of the flaky stuff? Belt sander work the best? (How do you decide if you need to pull up the boards and do more work than just repainting?)
Then, once I've sanded down, put what kind of caulk between the grooves, then wood permanizer, and I've already bought a porch & floor oil enamel paint-is this ok?
Thanks in advance for your wisdom!
Personally, if it needs THAT much repair and prep. I'd be sorely tempted to replace it.
Ya have lead paint likely, and you do not really know what the substructure is doing as far as rot or termite/ant stuff.
It would just be a wild guess on my part to advise how far you want to go, without seeing it in all its glory.
Sorry, if that didn't help too much..but it really is a judgement call. Spheramid Enterprises Architectural Woodworks
I kidnapped the runaway bride..her eyse weren't like that in the before pics.
I don't think it is that bad, my "beginner" description was misleading! I'm going to restart this as a new msg and try to include pictures so you can see it!
Painting of underside is not necessary.....no primer when using the Ben Moore....and glue is a no-no on flooring.
J. D. Reynolds
Home Improvements
"DO IT RIGHT, DO IT ONCE"
By the way, I will be attaching the porch flooring to the joists similar to how a table top is attached in fine furniture-from underneath thru slots in a bracket. Thus allowing the floor to expand and contract without splitting or cracking. The porch is surrounded on 3 sides by brick wall and I will be allowing 3/8"-1/2" clearance for any expansion or contracton.
you didn't say how wide this is..point is, my chestnut dining table is 43.5'' summer, 42.75 in winter..
1/2 to 3/4 gap is tite..glued this will be ONE BIG slab..don't do it.
View Image
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
The guy at my B Moore store told me the same thing about priming and I followed his directions. His rationale is that the top coat is harder than primer, so would move relative to it and pop off. So I did what he said. Despite this (or becasuse of it) the top coat has peeled several times and has very poor adhesion to the recommended "primer". The "primer" sticks well, however! I complained and got shrugs and eye-rolling for a response.
whether to seal the bottom side depends on whether you anticipate seeing a source of moisture on the bottom. If the wood can absorb moisture from the bottom side while the top stays dry and hot in the sun, you will see cupping as the bottom expands while the top remains relatively stable.
is there a roof over this to keep most of the weather off it?
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
Nope, there's no roof. Just surrounded on 3 sides by 2 story brick walls. This porch is 85" wide and 13'-7" long. I'm afraid I've exhausted all suggestions. I originally posted this about 10 months ago and am finally getting around to doing this job. I've considered the new composite stuff and have listened to everyone here both last year and this week. The joist spacing varies from 19" on 4 of the spans with the last span between joists at 25". That's why I went to 1" thick. I can not change the existing joists and they are sound.
I've already purchased the fir and have rabbetted the edges to create the lap joint. I couldn't find any one to supply tongue and groove 1" thick stuff (economically). Based on last year's post here on Breaktime I decided to go with the Gorilla glue. But now I'm considering not doing that. You see the difficult part of all of this is that I need this porch to act as a roof to keep things dry, yet be able to walk on it. I've started to rip off the old porch floor already.
Now after all of that and what's been said here today I'm considering going to exterior plywood and then laying some sort of roofing sheeting over that. Any ideas on where I can get this roof sheeting to cover the plywood? What's the best stuff to use? I will also install flashing around the sides with construction adhesive (don't want to drill into the brick). I could always sell the fir boards I guess.
since you are this far, I would still go ahead with this fir and glue or Lexel. Geocell caulk would do it too.
But you weakest point in this design is going to be the brick wall flashing. If you don't cut in properly, you WILL find water ruinning in.
To be more sure that it doesn't get through, you could do the sheathing and bituthene but then you could count on the fir absorbing water from behind when moisture does get trapped in there. the system would be more waterproof but not last as long.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
If it absolutely must be waterproofed fully, then you need to sheathe, do an EPDM roof, and sleepers to suppport the deck.
I still think that using the Gorilla glue will give you a decent compromiose and shed 99% of the water as long as there is a pitch and the grian of wood runs with the water flow.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I still don't think the gluing is a good idea... fir will move +/- 1/8" per foot across the grain, so he's got a potential for almost 2" of movement. It will probably shrink right away once it gets out in the sun. And I don't see making it waterproof--where else in construction do we try to make a waterproof surface out of t&g solid lumber with nothing over it? Personally I'd install the decking as normal, nailed or screwed down, and abandon the idea of storage. If absolutely necessary one could use the fir on sleepers over a roofing system, but there would need to be some significant breathing space under the decking and the joist height is already set.
Since the porch is 85" wide , 1/8" per foot of wood movement calculates out to .88" not 2". I may have misquoted the width of the porch.
If I do use an EPDM roof membrane, does anyone know what I can put on top of that so foot traffic won't puncture it? I can't do sleepers and another deck on top of that, it's not possible in this case because there are doors that swing out onto this porch and any extra height would interfere.
I appreciate everyone's help by the way, but to tell you the truth I am now at a loss as to what to do for the best solution. So many conflicting opinions. I just want to do this right. I should say that the existing deck has lasted almost twenty years or possibly 30 with its t and g 3/4" thick boards and the plastic sheets on top of that. The sheets are what caused the rot they didn't allow the water that got trapped underneath them to evaporate thereby causing all of the rot. They were nailed down with no glue and go right up to the brick almost. The porch perimeter was heavily caulked with tar where it met the brick.
I was the one who said 1-1/2" of movement, and I think I thought you'd said 13 feet wide.... anyway... in my opinion, there really isn't any way to create a permanently waterproof deck by caulking and painting t&g.
You could investigate a product called Gaco or Gacoflex. It's a waterproofing system for plywood decks. It's been eons since I saw it applied but I believe they just ran it over 3/4" t&g plywood. There are other products like it. Look in your yellow pages under waterproofing contractors and see who's who. I had a waterproofing guy come out and waterproof and flash a plywood deck so that we could pour a slab over it and set flagstone. They used stuff you can't buy at Ace... a multiple coat product applied with layers of fabric. It built up about a 1/4" or so. We buried the end result under stone but they could have finished it with a walking surface if we wanted one.
Reread what Piffin said about the brick flashing. All that tar around the edge sounds nasty and ineffective. You need to cut in a proper flashing around there. If you hire a waterproofing pro to do it they'll handle that too. Then you could store the Mona Lisa under the porch safely.
what Piffin said
EPDM with proper sidewall flashing
as far as the walking surface, this is a perfect product with minimal thickness
http://csi2003.pipelineinteractive.com/documents/ResLib/Pavers_and_Walkways_Briefolio.pdf
do not lay rubber membrane directly over a nailed wood substrate. the nails will back out over the years and puncture the rubber.
carpenter in transition