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Posted

Here are three photographs of gaps in the exterior finish of a relatively new home. It's one of those conditions that causes me to have rather convincing arguments, even with myself, regarding whether to recommend sealant or not.

The argument can be made: "No don't seal this gap so water can come out from behind the vinyl siding." Yet, how can this occur without any flashing turned out from behind the siding onto the porch surface?

A similar argument can be made: "Since concrete is porous and prone to stay pretty damp for long periods of time, sealant will hinder evaporation from the slab." - a reasonable thought.

My bigger concern tends to be: "Where does torrential and wind-driven rain go once it enters this gap? What's becoming and staying wet that wasn't intended to?"

There may, in fact, be other concerns that I have not raised, which you are welcome to add.

I usually feel more comfortable making certain that paths of moisture intrusion, when no known drainage path is present, are sealed. I, therefore, tend to recommend that these gaps be sealed. (especially the gap in the door threshold).

So, what do you think? What concerns drive you to lean one way or the other regarding gaps, such as the ones in the photos?

I for one look forward to some valuable insights that may persuade me one way or the other instead of being quite as torn as I have always been.

Let the discussion begin...

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Posted

Yet, still the bigger question remains. Where is water going? What forms of ongoing water damage are possibly occurring? If we aren't going to use sealant, what's missing to prevent moisture intrusion? I always hate seeing these Achilles heels in the exterior. They drive me nuts. What needs to change in the design to completely eliminate the vulnerablility? This is where it begins to become a more difficult question than seems initially apparent. That's why I teed this situation up. I see it as a disign flaw altogether and always have...

Is there a silver bullet out there?

Posted

For the siding to hardscape, properly flashed this type of joint does not frighten me. If it is properly flashed sealant does frighten me. Do you have any indication that water is getting in and doing damage?

Does the siding need clearance? I am not familiar with vinyl siding requirements.

As far as the threshold goes seal it up. Even if it has a pan flashing keep the water out.

Posted

Well, it's a no brainer that water is getting behind the porch slab. And, once that has occurred, then the whole question of where it's going and how it gets out arises. That's where I go crazy. I don't like to know water is getting behind or under anything, period.

The whole idea of drainage planes is an emergency backup system for the "just in case". I honestly have no idea where this water goes, but we all see rotted bandboards and joist ends behind porches like this every day. There's just got to be a better way to do this.

As far as clearance between the siding and slab goes, if there was a desirable clearance, I don't see how that remedies or prevents anything without some form of flashing that directs water coming from behind the siding onto the slab while denying water on the slab an avenue behind the slab.

I've never understood why this design flaw hasn't been eliminated.

Posted

I'd say that 90+ percent of all homes around here have post and beam construction on the main floor, so there's no rim joist to deal with. As long as the trim board overlaps the foundation, this would most likely never be a problem.

If you have joist construction, there won't be adequate overlap, as the rim joist is at or below grade from the porch surface. That's where proper flashing and WRB details are needed-- we know that probably won't happen.

Here's a fix: Prevent water from ever hitting these areas by installing a roof covering.

Posted

That door is toast, that jamb will be mush in a year or so. The crappy caulking job leads me to think the pan flashing is also missing. The brickmold has wicked so much water already that it won't hold paint. Then there is vinyl siding and no trim, if the sider didn't have a brake to wrap the door frame and brickmold do you think he got any of the siding details right? The good news is they'll be able to see how rotten the rim is when they replace the door.

Tom

Posted

That door is toast, that jamb will be mush in a year or so. The crappy caulking job leads me to think the pan flashing is also missing. The brickmold has wicked so much water already that it won't hold paint. Then there is vinyl siding and no trim, if the sider didn't have a brake to wrap the door frame and brickmold do you think he got any of the siding details right? The good news is they'll be able to see how rotten the rim is when they replace the door.

Tom

This is the norm here in new construction, which absolutely drives me nuts. I can never get that haunting question out of my head: Where is all the water ending up?..

Posted

Water seeks the lowest point. It is seeping down the side of that threshold plate. It hangs out for awhile, soaks in the brick molding, door jamb, etc and then it trickles down a little more and on and on.

If folks would install doors like windows are installed we would have less problems.

  • 1 month later...
Posted

Well, I suppose this says it all...

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No framing damage, but I was surprised there wasn't.

Posted

The good news is they'll be able to see how rotten the rim is when they replace the door.

Tom

Ha!

No doubt. But for the phrase "visible or apparent"... Actually the floor system is engineered joists with wood top and bottom cords and an OSB web, so it may fare better than your average solid woor framing - a bit more airy - evaporation friendly.

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