OP
CurlyDave
Elite Member
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A Question for Contractors
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orezok
Elite Member
Dave - I went by one of my projects today, a high school, and looked at the tile on the second floor exterior walkways. It also is a porcelain tile and to my surprise we have runs of almost 200' without a single expansion joint and standard grout in the joints. We have been using this same detail for several years now without any problems with tile coming loose.
Our winter temps are close to or slightly below freezing and summer will hit 120+. The kicker is that we pour 2" of light weight concrete over a steel deck. Tile is then thin set.
I really believe that your problem is with the wood framing, not that it is inadequate, but perhaps not the best application. The modulus of expansion for concrete & tile is more than double that of wood. Something has got to give.
I would cut an expansion joint every 20' or so all the way down to the wood deck and fill with an elastomeric sealer. This hopefully will allow the concrete/tile to move independent of the wood and reduce your problem.
Our winter temps are close to or slightly below freezing and summer will hit 120+. The kicker is that we pour 2" of light weight concrete over a steel deck. Tile is then thin set.
I really believe that your problem is with the wood framing, not that it is inadequate, but perhaps not the best application. The modulus of expansion for concrete & tile is more than double that of wood. Something has got to give.
I would cut an expansion joint every 20' or so all the way down to the wood deck and fill with an elastomeric sealer. This hopefully will allow the concrete/tile to move independent of the wood and reduce your problem.
OP
CurlyDave
Elite Member
Our winter temps are close to or slightly below freezing and summer will hit 120+. The kicker is that we pour 2" of light weight concrete over a steel deck. Tile is then thin set.
Do you have a roof over the walkways?
I didn't realize the CTE of wood was less than that of concrete and tile.
Anyway I am attaching pictures of the deck, more in the next post.
Do you have a roof over the walkways?
I didn't realize the CTE of wood was less than that of concrete and tile.
Anyway I am attaching pictures of the deck, more in the next post.
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orezok
Elite Member
Some decks are covered others only partially and all are soffited below, but otherwise open to the weather.
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OP
CurlyDave
Elite Member
I checked again and the beams are not Glulams, they are Versalam, which is a better material for this application. They are sheathed in Hardiboard. I measured, and on the east and north sides they are 18" x 5 1/4" and on the West side, over the garage doors, they are 24" x 5 1/4".
The posts under the beams are 14' tall, 15' 6" on the west side where the garage is. They are 6" x 6" pressure treat. The stone-sheathed post bottoms are 26" and 44" tall. Under the stone is 12" x 12" hollow cinderblock, concrete filled. The piers are 4' x 2' with lots of rebar and 4 pieces of #4 bar coming up the interior of the block. Galvanized post bases and caps.
The west side is where the tiles are coming loose the most, on the north side, they are almost perfect, and very little deterioration on the east side.
* * * *
The contractor was out this morning and what he wants to do is take up the tile in a 20' x 10' section on the west side, let it dry for about a month, and test the polyurethane grout in this section. He thinks he can tell just by examining it whether it will last through the winter.
My cost is only going to be $300 - $400 on the test section, maybe even less.
Right now my inclination is to let him go ahead and do that. The biggest reason is that he told me he has insurance which covers failures like this and if we can't get a good resolution, he feels he can just turn it over to his insurance. If I tell him how to do the job instead of of just making suggestions, the insurance is not going to cover it, so I have to tread lightly. OTOH, he is a very sensible guy and we are both in agreement on how to proceed.
If the test section doesn't look good, then I will suggest expansion joints in the concrete underneath the mortar.
The insurance adds a whole new dimension to the problem, especially since the contractor is willing to help me if it gets to that. We would both prefer not to have to use the insurance, but at least no one is going to go bankrupt if worse comes to worse.
* * * *
Some of the things that make me feel good is that last year the efflourescence on the bottom of the headers was much, much worse than this year. Almost continuous along the bottom of the headers. The cause of these deposits is water coming through the tile, down the back of the headers, and evaporating from the bottom of the header.
Also, last year the grout was missing, as in totally gone, not just deteriorated, from about half the deck area, this year it is much better. And the efflourescence on the surface of the deck is much, much less than last year.
The posts under the beams are 14' tall, 15' 6" on the west side where the garage is. They are 6" x 6" pressure treat. The stone-sheathed post bottoms are 26" and 44" tall. Under the stone is 12" x 12" hollow cinderblock, concrete filled. The piers are 4' x 2' with lots of rebar and 4 pieces of #4 bar coming up the interior of the block. Galvanized post bases and caps.
The west side is where the tiles are coming loose the most, on the north side, they are almost perfect, and very little deterioration on the east side.
* * * *
The contractor was out this morning and what he wants to do is take up the tile in a 20' x 10' section on the west side, let it dry for about a month, and test the polyurethane grout in this section. He thinks he can tell just by examining it whether it will last through the winter.
My cost is only going to be $300 - $400 on the test section, maybe even less.
Right now my inclination is to let him go ahead and do that. The biggest reason is that he told me he has insurance which covers failures like this and if we can't get a good resolution, he feels he can just turn it over to his insurance. If I tell him how to do the job instead of of just making suggestions, the insurance is not going to cover it, so I have to tread lightly. OTOH, he is a very sensible guy and we are both in agreement on how to proceed.
If the test section doesn't look good, then I will suggest expansion joints in the concrete underneath the mortar.
The insurance adds a whole new dimension to the problem, especially since the contractor is willing to help me if it gets to that. We would both prefer not to have to use the insurance, but at least no one is going to go bankrupt if worse comes to worse.
* * * *
Some of the things that make me feel good is that last year the efflourescence on the bottom of the headers was much, much worse than this year. Almost continuous along the bottom of the headers. The cause of these deposits is water coming through the tile, down the back of the headers, and evaporating from the bottom of the header.
Also, last year the grout was missing, as in totally gone, not just deteriorated, from about half the deck area, this year it is much better. And the efflourescence on the surface of the deck is much, much less than last year.
Attachments
OP
CurlyDave
Elite Member
Some decks are covered others only partially and all are soffited below, but otherwise open to the weather.
Looking at your pictures, I am getting pretty hopeful here.
The big difference is that you have steel under your decks and I have wood.
I would cut an expansion joint every 20' or so all the way down to the wood deck and fill with an elastomeric sealer. This hopefully will allow the concrete/tile to move independent of the wood and reduce your problem.
If one were more concerned with doing this absolutely bulletproof than saving what exists, would that kind of expansion joint be preferred over something like laying sheets of ~ 14 ga galvanized steel, overlapping, on top of the OSB and then pouring a 2" layer of concrete? This would give me concrete over steel, just like at your high school, with the steel somewhat free to slide on the OSB to relieve stress.
If you don't like that idea, I am going to print out your pictures and show them to Mike, the tile contractor.
Looking at your pictures, I am getting pretty hopeful here.
The big difference is that you have steel under your decks and I have wood.
I would cut an expansion joint every 20' or so all the way down to the wood deck and fill with an elastomeric sealer. This hopefully will allow the concrete/tile to move independent of the wood and reduce your problem.
If one were more concerned with doing this absolutely bulletproof than saving what exists, would that kind of expansion joint be preferred over something like laying sheets of ~ 14 ga galvanized steel, overlapping, on top of the OSB and then pouring a 2" layer of concrete? This would give me concrete over steel, just like at your high school, with the steel somewhat free to slide on the OSB to relieve stress.
If you don't like that idea, I am going to print out your pictures and show them to Mike, the tile contractor.
EddieWalker
Epic Contributor
Dave,
Sounds like you got some good ideas and options. I like the test idea allot. See what it does and how it holds up. That makes allot of sense.
From what you've written, it sounds like you built the deck plenty strong. Probably stronger then allot of elevated parking pads that I've seen!!! Loads sure are not going to be an issue.
One thing that I don't understand is how are you controlling the side to side movement of the deck? The posts don't have any diagonal bracing on them. With all that height, I would think it would be fairly noticeable. Since you didn't mention any movement, and don't feel that's an issue, I'm mostly just curious how you stopped it from happening?
Eddie
Sounds like you got some good ideas and options. I like the test idea allot. See what it does and how it holds up. That makes allot of sense.
From what you've written, it sounds like you built the deck plenty strong. Probably stronger then allot of elevated parking pads that I've seen!!! Loads sure are not going to be an issue.
One thing that I don't understand is how are you controlling the side to side movement of the deck? The posts don't have any diagonal bracing on them. With all that height, I would think it would be fairly noticeable. Since you didn't mention any movement, and don't feel that's an issue, I'm mostly just curious how you stopped it from happening?
Eddie
JB4310
Super Member
Probably a foolish question but is that exterior waterproof grout?
From those pictures it is evident there is water permeation, just can't tell if it is occurring before the tiles are lifting or only after the damage is done. Water penetration along with freezing temps would do the damage by itself independent of any other factors.
You mentioned the North side as being the least affected, to have freeze/thaw damage you have to have the thaw, it's as important as the freeze, often times as would be expected there is not enough thaw on the North side. So the constant colder temps are actually preventing that process.
Not familiar with your climate but I thought there was mention of below freezing temps. do you get snow and ice accumulation?
JB.
From those pictures it is evident there is water permeation, just can't tell if it is occurring before the tiles are lifting or only after the damage is done. Water penetration along with freezing temps would do the damage by itself independent of any other factors.
You mentioned the North side as being the least affected, to have freeze/thaw damage you have to have the thaw, it's as important as the freeze, often times as would be expected there is not enough thaw on the North side. So the constant colder temps are actually preventing that process.
Not familiar with your climate but I thought there was mention of below freezing temps. do you get snow and ice accumulation?
JB.
orezok
Elite Member
You wouldn't actually need the steel. We use it because our schools are of "fireproof" construction, that is we use no wood. The metal we use is steel decking which is actually a fluted roof deck, and the concrete is somewhat locked into the flutes and moves with it. Again the coefficient of expansion of metal is more similar to concrete/tile than wood. You can accomplish the same thing by just putting a slip sheet down over the wood, such as 15# felt.
PILOON
Super Star Member
Been following;
I like the idea of 'controlled cuts' in the concrete base (to co-incide with a grout line).
That would eliminate any expansion related causes.
Also you mentioned a treatment to waterproof the concrete, could it be a silicone based product? that in itself could explain the lack of adhesion also might that product simply be filling the concrete pores and preventing the tile morter from adhering?
For outdoor waterproofing I seem to recall that one was to add a seeler to the grout and that would prevent water infusion.
I tiled my outdoor entry slab last summer and biggest problem was that the slab sucked the tile thinset dry before I could lay a tile so I simply wetted the slab before trowelling the thinset. The winter here went to -30 and now that all is melted/thawed a few times I can report success.
I like the idea of 'controlled cuts' in the concrete base (to co-incide with a grout line).
That would eliminate any expansion related causes.
Also you mentioned a treatment to waterproof the concrete, could it be a silicone based product? that in itself could explain the lack of adhesion also might that product simply be filling the concrete pores and preventing the tile morter from adhering?
For outdoor waterproofing I seem to recall that one was to add a seeler to the grout and that would prevent water infusion.
I tiled my outdoor entry slab last summer and biggest problem was that the slab sucked the tile thinset dry before I could lay a tile so I simply wetted the slab before trowelling the thinset. The winter here went to -30 and now that all is melted/thawed a few times I can report success.