I have to replace the decking on two tongue and groove porches (110 sq. ft. each) because whatever wood was used (the cheapest possible), several of the boards have buckled. The joists have been inspected and, aside from the peeling paint, they’re sound. (photo enclosed)
I suspect that the problem was caused by the boards being placed together too snugly to allow the boards to expand with the weather extremes here in Chicago.
I’m planning to replace the boards with factory primed, 3″ x 8′ Douglas fir (3/4″ thick), attached with a pneumatic floor nailer.
Can anyone advise me on how to get the proper spacing/snugness? Is there such a thing as too tight? Are there other things I can do to prevent the new boards from buckling?
Thanks.
Neal
Replies
T&G Fir Flooring is supposed to be tight as can be. That's partly why the nailers for them are designed to apply pressure toward that end.
It appears that the boards that have buckled did so because they are old, haven't been properly painted/maintained, are nailed into a joist of insufficient condition and/or are probably 80 years old already.
You may think your joists are sound because you see them from the bottom but it is common for them to rot out only from above and in the center... therefore, you see the other three sides which appear to be ok.
So, keep them super tight.. be sure they are dry when you install. Then paint well with oil-based porch floor paint. I have a secret recipe that will guarantee you years of worry free usage.........
The first coat of oil-based paint should be thinned into a 2-part paint, 1 part thinner mixture. Apply this liberally and allow to DRY COMPLETELY. Overnight if needed. This coat will appear similar to a heavy stain and the reason for thinning so much is that it will soak into the wood.... pnentrate into the fibers and give a good bite and subsequently become an excellent layer for the second (final) coat to adhere to.
Apply the 2nd coat without thinning.
This will yield and paintjob that will protect your wood very well for many worry-free years.
http://www.peteforgovernor.com
One more thought. It is possible, especially if this is a newer porch, that the last guy ran out of nails in his nailer and did not realize it. It is kind of hard to tell if you are not carefull. If this happened, that buckled board would easily result from a strip of T&G that wasn't nailed completely.
http://www.peteforgovernor.com
That sounds extremely useful. Thanks.Here’s one more clue that might be useful: even though they're T & G boards, they've been face-nailed. So it’s easy to see that all the nails are in. Despite this, the buckling (swelling?) pulled the boards out with the nails.Your point about where rot lives are well taken. I will pull up some boards and check even more closely for rot. Though, so far, there doesn’t seem to be any. At this point, I suspect it’s the first two reasons: old and improperly maintained.Also, I really appreciate you sharing your secret recipe. Does it still work on wood that’s already been primed? Won’t the primer keep the paint from penetrating the wood fibers?Neal
The only thing that I will add is when you paint those boards, is to paint the entire board. That is both sides and the tongue and grove as well. Don't for get the ends. That seals the entire board leaving no room for water to get into the fiber. Do all of this painting before you put the floor down.
DaneI will always be a beginner as I am always learning.
IMO, the source of the primary problem here is a no-brainer. Wood expands and contracts with varying amounts of moisture content. Your floor buckled because the boards are now bigger/wider than they were at the time of installation………..and they had no buffer zone to expand into because they were laid tight to the two end walls.
The only way you could expect to lay these boards dead tight to one another AND to the two end walls AND to never encounter a future buckling problem if the finish is allowed to deteriorate and the boards to become rain-soaked …….is to have the lumber at the fiber-saturation point (28%) when they were laid. If laid at the fiber-saturation point, the T&G's may or may not be deep enough to remain engaged with one another when the lumber dries down to it's lowest EMC for your locale. The narrower each board, the better the odds that they'll remain fully engaged when at the lowest EMC. This is all based on simple and well-known wood physics.
http://www.woodbin.com/calcs/shrinkulator.htm
There are other methods of laying the flooring without having them wringing wet (which is actually just preparing for poor future maintenance) and that is to lay the floor in the most humid part of the year, having stacked and stickered each board outside and under roof on site (for a couple weeks anyway). This would provide for a reasonable expectation as to annual maximum board width IF the floor finish is well-maintained. If that finish isn't well-maintained and rainwater is allowed to soak the boards, you can expect the total width to increase further and so must allow some buffer room for additional expansion. That means don't fit the ends dead tight to the end walls , but leave a ¾" gap or so on each end, which you would cover with a piece of shoemolding or similar……….the same as one would do when laying interior hardwood flooring.
http://www.nofma.org/
The practices of acclimating the flooring to its new home to avoid problems, such as your porch is having, is both common and highly advisable……..and that's for INTERIOR flooring where there's no expectation of rainfall on the floor and where it is usual these days for humidity levels to be controlled via central AC. The need of acclimation, proper installation and finish maintenance is evermore important on an exterior T&G porch floor.
I've seen the same problem that your porch is having (that made me near sick to my stomach) throughout the entire third floor of the huge old piano factory where our shop was located some years back. (We were on the second floor) The owners allowed the flat built-up roof to deteriorate and water poured in, dramatically heaving the beautiful solid cherry floors that had been there for nearly a century. The floor looked like a series of wooden waves cresting somewhere around 6"-8" high every 8' -10' lineal or so. Truly sickening. Resolution was to hire the cheapest carps they could find to cut out those sections and replace with plywood.
Knowledge is power, but only if applied in a timely fashion.
Edited 7/16/2005 1:24 pm ET by GOLDHILLER
Edited 7/16/2005 4:08 pm ET by GOLDHILLER
Another reason for the failure could have been that the flooring was only painted on the top side, rather than on all 6 sides as discussed above. This, and inadequate maintenance (re-paints) would allow the existing wood to take on too much moisture, expand a great deal, and buckle. The no gap at the edge of the floor would be a contributor too.
We also can't see from your pic whether or not this porch floor has appropriate pitch to it to provide for rapid drainage.
If water stands or pools on the flooring, the battle between the floor finish/water repellant favors the water penetrating and soaking the wood.
There is plenty of pitch for water run-off. At first, I thought the deck footings had subsided. However, professional inspection determined that they hadn't. The original contractor just wanted rapid water movement off the deck boards.I'm sure it's me being extremely dense here and I appreciate your collective patience. I now plan to paint the deck boards on all sides before installing them. But I'm still not sure about the gapping, if any, necessary to prevent buckling when nailing them down. Wouldn't there be some normal expansion of wood caused by Chicago's significant weather changes even with the paint? Are you saying that the layer of paint on the tongues and grooves will provide enough room for natural movement?Your observations and suggestions are much appreciated.Neal
"Wouldn't there be some normal expansion of wood caused by Chicago's
significant weather changes even with the paint?"That's the reason for first acclimating (2-3 weeks) during the most humid time of the year and then install the stuff. The wood should then be pretty much at its "largest" size.....if the acclimating is done properly and for long enough. (Acclimation should ALWAYS be done with bare wood prior to applying any type of finish whatsoever because a finish will impede/slow the process.) Once acclimated during the high humidity period, you can go ahead and lay the boards snug to one another because any appreciable changes should be in the direction of individual board shrinkage (smaller)….when humidity levels drop during the rest of the year. That won't cause the floor to buckle from growth, but each board to shrink a bit.However, to play it safe……… acclimate in high humidity (right around now in Chicago......I'm bout 2 1/2 hours from you) ........and then also provide that buffer gap at the ends between the two walls. Easy to do. Lay a piece of 3/4" wide stock in there, butt your first piece to it and lay away. When done, grab that starter piece and yank it out. Leave the same gap on the end of the floor where you finish up."Are you saying that the layer of paint on the tongues and
grooves will provide enough room for natural movement?"You've sorta lost me. Not sure what you mean or thought I did. <G> Fact is, I didn't suggest paint and it wouldn't really be my first choice of finish for a porch floor. I'd be more inclined to use a quality deck sealer myself as renewal is lots easier and the result better. No scraping or sanding is involved and a water repellant/deck sealer can penetrate easier down into those T&Gs during subsequent treatments/renewals.The notion here isn't to attempt to hermetically seal up the wood with numerous thick coats of X,Y or Z......but rather to prevent the absorption of water DROPLETS. The exchange of water VAPOR from changing humidity levels is to be expected and really can't be stopped anyway. If you've acclimated the bare wood flooring to the high humidity part of the year prior to laying it, then having it return to the same EMC next summer isn't a problem, nor undesirable. What you need to do is prevent the wood from becoming unnecessarily soaked by rainwater and the like…if you want to prevent the chances of encountering buckling again. That type of "soaking" always comes in the form of droplets, not vapor (unless your porch is located inside a steam bath). Water repellants and deck sealers will prevent the absorption of these droplets IF they are quality goods and are kept up. Presumably, this floor of yours survived for some time without buckling (doesn't look brand new in the pic, but rather a few years old). Probably because it didn't absorb sufficient water to swell enough to jamb itself against those end walls and then buckle up to relieve the pressure. I'm guessing the floor finish (whatever it was/is) ….was maintained well enough until recently. If you want to know just how much the floor is currently swelled beyond what it previously swelled……..just measure the difference. Let's say you have 3 ¼" T&G fir there. There's currently four pieces buckled off the floor. 4 x 3 ¼" = 13". Now measure the distance between the closest boards of the reacting areas that didn't buckle up (those that are still laying down flat. Let's say one set measures 5" and the distance between the others is 5 ½". 13" minus 10 ½" = 2 ½". That 2 ½" of accumulated "extra" wood width from the swelling of the entire porch floor had to have some place to go….and it didn't. So it heaved up in the two places you see under your feet out there. While you can't prevent the absorption of atmospheric humidity and the accompanying swelling from that, you can work with it/tame it….to your advantage…..and you can prevent the absorption of rainwater and such……..and that is what causes the extreme swelling you need to avoid with the new floor. Just keep the water repelling finish in tact at all times. An ounce of prevention and all that. Removing snow accumulations before they melt will also be to your advantage.Your current floor can be saved to a usable result as is ........although the end result may not be to your liking because it means placing a couple different sized pieces in there. You'd simply remove the pieces that are heaved up and cut custom sized pieces to replace them. Knowledge is power, but only if applied in a timely fashion.
Edited 7/16/2005 6:15 pm ET by GOLDHILLER
On the interior of a home I always leave 1/4" gap between wall and flooring. On a porch Iwould leave 1/2". This would be covered with mop board. The floor now has a place to expand to. Put a match book cover under the mop board(base) before you nail it. This insures that the floor can expand and contract under it. As far as the longevity of the joists: I use to use "joist tape" ontop of exterior joists. Over the years I discovered it extended the joist life by 8- 10 years!! It sheds the water!! I now use Ice & Water Shield (Ask for it by name). It works ever better, as it seals around the nails and screws that penetrate it!! Cut it 2" wide. This will divert any water away from the joist. Good luck, and if your close enough, I'd love to come to your first BBQ
If, at first, you fricascee, fry, fry a hen!
why do you call it 3x8 when only 3/4 inch thick just curious unless it was a mis type
or it is some regional thing with that style of deck board
like aussies calling a stud a 4-be-2
I'm happy to see this discussion. I've been wondering for a couple years if we did the right thing in re-building our porches. The reason is that the both porches have cracks between the T&G so the rain leaks into the upstairs porch and comes out the beaded board ceiling downstairs. Not only will there be rotting problems but there are two electrical boxes in that ceiling for fan/lights.
We had full one inch by 3" treated T&G made. It sat, spread out, on the porches for over a month. We primed all sides with an acrylic sealer. Covered the joist with 30# felt and painted with oil based deck paint. Our guys were installing the downstairs with staples when I kindly pointed out that I didn't really care for staples. They finished out with them and had buckling problems. They installed stableizers (cut-offs from the T&G from the underside with screws). Upstairs we used three inch screws and ring-shank nails --- no buckling. On both porches we pulled boards snug.
Now, on both porches, when the weather is dry, the T&G shrinks and pulls the paint apart between each board. This allows rain to enter and get to the aforementioned structure and light fixtures. Last summer I attemted to remedy this by using one of those hair-do bottles, with a pointed tip, to fill the gaps with paint. I was pretty happy with that until this summer when the dry weather came the boards pulled apart again.
This is what I'm thinking now. I plan on getting some fine sawdust and mixing in some acrlyic sealer, just enough to make it damp. Then, tamping this into the cracks, wipe with a rag and paint over when dry. Of course, this would have to be done when the porches are as dry as they can get so the cracks are at the widest.
Appreciate any comments.
Here is a picture of the porches at the bottom of this page:
http://www.geocities.com/annajo1009/
xpayroll
Edited 7/17/2005 12:13 am ET by xpayroll
That's a WAY cool looking house...
IMO, if you sucessfully fill the gaps between the dry boards, you will have buckeling problems down the road.
As Matt
You don't say what species was used for this treated stock and I'm not familiar with what is commonly used in Texas for this product. I'm assuming that vertical grain stock was not used; not that I think doing so would have made the difference between success and failure concerning that second story porch floor. Since the movement of a 3" wide board of an average species of wood ranging all the way from the extremes of the fiber-saturation point to dead dry wouldn't result in the approx. ¼" of movement that would be required to disengage any normal-ish T&G…… we can assume that when you say there are cracks between the boards…….you don't mean between each and every board. Nonetheless, I'm sure it doesn't matter an iota to you how frequent those leaking cracks are, you just don't want the leaks. The fact is that upper porch is being asked to serve as a roof for the lower porch and T&G lumber is not generally considered a suitable water-shedding roofing material. Whenever T&G is or was……. used as a roof deck, shingles or some other manner of roofing material is applied over it. I wouldn't ever use it, and it alone, as a combo porch floor and roof…..and expect it to be water-tight……especially on a flat roof. You shouldn't either. Those pieces of flooring lumber are going to continue to change dimension with changes in ambient humidity levels, exposure to the sun, drying wind, etc. Stuffing the cracks with various concoctions doesn't really stand a chance of working for very long unless that filler is something like a poly-caulk or Big Stretch. Even that would be dubious on a porch floor and would no doubt require periodic renewal.IMO, the only way one could feasibly get away with keeping that wood porch floor up there exposed for viewing (ah, the romantic look of it all) and not have water leakage where you didn't want it….. is to build a functional water-shedding roof out of EPDM or similar and float the exposed T&G floor on sleepers over the top of that.If you don't care to go thru the work and expense of that, you could consider applying a period canvas floor over the existing T&G as it is. That too will have to be maintained and renewed when necessary.
Edit: How about this? You first lay down a covering of Grace (I&W membrane) and then your loose laid/perimeter fastened only ......canvas floor over that. This way if the canvas deteriorates a bit before you get it renewed, you shouldn't have any leaks thru to the underlying floor or beadboard ceiling. Fact is, your contractor should have advised you of the high likelihood of failure when this current approach to those floors was first voiced.When you say the lower porch floor buckled and indicate you think this is because staples were used instead of screws, I can't help but think you really mean that the boards cupped. If the top side of those boards are exposed to the drying sun and wind and the underside of them is exposed to damp/wet soil, this is to be expected. If you didn't, you should have laid a plastic vapor barrier under there to minimize the differences which would contribute to this cupping. If it did actually buckle because there was the expectation that one could …….or lack of foresight concerning the ability to…… stuff 11 pounds of potatoes into a ten pound sack……. then it's a sure indication that something was not properly prepared, engineered or executed.Wood is going to move with changes in its moisture content, be that from atmospheric moisture, rainfall, drying sun and wind, etc. You cannot stop this phenomenon. If you try to restrain/over-power the physics of this………again, you lose. Take the example of a wooden hammer handle that becomes wet. The metal of the surrounding head restrains the wood from expanding and the end result is that the wood compression sets. When it dries out again, voila…..the hammer handle is loose, not as it was before it became saturated. This is the same thing that will happen if you try to fully restrain the naturally occurring movement of a wooden floor/ the members thereof.
The only way to keep a piece of wood at a constant dimension is to keep its moisture content constant. (I don't personally know of any porch floors that are kept at a constant moisture level) Even though you can't stop this movement……it is predictable and you can use that information to your benefit as you engineer a project that uses wood. Trust me, you can't cuss or will or beat that wood into submission because it must respond to the laws of physics. Learn the predictable responses of those laws and you're well on your way to better engineering and likely better results.
Knowledge is power, but only if applied in a timely fashion.Edited 7/17/2005 11:44 am ET by GOLDHILLEREdited 7/17/2005 11:50 am ET by GOLDHILLER
Edited 7/17/2005 12:56 pm ET by GOLDHILLER
I live 90 miles south of you and I don't suggest using t&g doug fir. I have done only two t&g porch floors down here with it. One faced east and got very little weather, it lasted eight years. One faced North and caught everything Midway didn't, it lasted five years. Both were pre-primed with oil and one coat of finish before install with one finish coat after install. The northern exposure (my own!) was lightly sanded and re-painted each spring!
Look for another product. You will be money ahead. Composite materials seem to weather great here, Trex is my favorite this year. It isn't t&G which to me is better because it never holds water. From your picture it seems that the porch was maybe a roof as well. In that case t&g may seem like your only option because it sheds water better then spaced boards. Use treated (ACQ)t&g, let it dry a few weeks before you install it. After you install it, either seal the top side only with a water sealer, stain it, or prime and paint the top side only. Treated lumber neads to breathe, I can't remember why. My new porch is treated (CCA) 5/4" x 6" painted white (every year), top side only. It is 6 years old and in great shape.
T&G flooring is supposed to be tight but your situation does look like buckling due to expansion and contraction. I expect that the flooring was placed up against a wall without room to expand. there should be at least 1/2 inch between the wall and beginning of the layout.
I would also prime the T&G 's and use a solid color stain since it is outside. Paint on a floor won't last long.