Exterior faux rock spanning dissimilar wall material
Hello, I would like to install faux rock on one of the exterior walls of my house.
The rock would span from grade to just below the first floor windows. The foundation is styrofoam block with peel and stick Supremo waterproofing over the styrofoam, the wall is a structural insulated panel with OSB, house wrap and rain screen on the exterior. It seems the normal thing to do is to install flashing where the wall meets the foundation and install siding above that flashing and the rock below the flashing on the foundation wall. But I want the rock to go from grade to just below the window. I guess I could install the flashing as normal and install the rock on the wall above the flashing and then install rock below the flashing to grade. But I don’t want a horizontal line of flashing to interrupt the layout of the rock.
There is a rain screen and I am using pressure treated 1″x2″ vertically every 16″ for that.
My question is: Can I just extend the 1″x2″ rain screen on the wall over the foundation down to grade and then use that 1″x2″ to fasten my mortar mesh to from grade all the way up to just below the windows? Or is there some risk that there may be movement between the wall and foundation, or some other concern, that would make this a bad idea?
Replies
I hear you ..
I hear you, I don't like the look of rock on a house that looks like it is floating 8 or 10 inches off teh ground. So you desire to run teh stone to groundis understandible. However, most stone manufacturers do not approve stone to ground installs.
That is issue number one.
Secondly, I have no expert here. Ok, that said. I think the idea of extending teh rain screen over the foundation has some merit. However, is your shelthing proud of the foundation? If so your strapping would be unsupported at the foundaiton level and the mesh might be springy. I would worry the mortar might crack. Secondly, if you run you rrain screen to ground it will defeat the purpose of the rain screen nd might even make the wall weter. This would be due to the fact that there would be little air movement in the screen and what movement there would be woud be moist air from teh ground.
Just some thoughts. Will be interested to hear others.
Exterior faux rock spanning dissimilar wall material
Hi Doright, thank you for your reply.
The sheathing and the exterior plane of the foundation ICFs are on the same plane, and I would have to make sure that I fastened the furring strips, that would extend down the wall onto the ICFs, to the connectors within the ICFs for a secure connection.
You raise a good point about this scenario defeating the function of the rainscreen if it terminated at or below grade, I never thought about that. I wonder if there is a way to address that issue at grade? Maybe I will have to have rock "floating" above grade but I think this looks so unnatural.
I guess no one cares.
Exterior faux rock spanning dissimilar wall material
Hi Doright, thank you for your reply however, I am at a loss to understand why you would say no one cares. I care and I am someone. Ultimately I believe God cares. Given your very good comments in your first post, I suggest that you care too.
Amen Brother
And my I call you brother? God does care. Got reminder for civility. (spelliong?)
I posted the "no one cares" post to try to bump your thread toteh top and to spur other responses.
And to be honest, I am interested in the post for selfish reasons as well. I too beleive floating stone is ... stupid looking ... however, ... NO ONE ELSE CARES or THINKS about that either. My wife for one. If you are going to build something to minic or replicate some historic detail like a stone foundation then it sould look like a foundation and not a majic trick.
So can you bring stone to grade? They say you should not do this with the fake stone, this is number one. Secondly, on the rain screen issue. I made a point, good or bad about killing the air flow, but frome what I understand the big issue with the stone veneers is that dampness through the stone continuially wets teh sheathing particularly with hydrolic presures. Therefore the rain screen breaks that presure. So, you might be fine, but air flow could never hurt.
What is rain screen?
I read it to mean a furred out sheathing away from the wall and house wrap that you attach the stucco lath and stone to. Is this open at the bottom? How do you keep it from being a critter haven? (particularly rodents)
If this is not an issue, I really don't see a problem with spanning the two types of wall as long as you do support the lower part (shimmed out or whatever) The wire mesh behind the mortar and the furring should hold it togetner.
.
Exterior faux rock spanning dissimilar wall material
Hi Greg, thank you for your reply.
What I mean by "rain screen" is essentially the air space/water drainage space created between the housewrap and siding by applying vertical furring strips over house wrap and then fastening the siding to those vertical furring strips, there is no sheathing applied to the furring strips. Instead of siding, I was intending on fastening the mortar mesh to the furring strips and then applying the mortar and then the rock to that. Do you think I would need to fasten sheathing to the furring strips for adequate connection of the mortar mesh and rock?
I would put stainless steel screening along the bottom of the rainscreen to prevent insects and critters from entering the space created by the furring strips.
I was wondering ..
I was wondering about thee need to add sheathing to the straping as well. Would the metal lath alone be too springy? Some kd kicks a ball hard into it , would the mortar joints crack? I suppose if your scree (spelling?) coat were think enough it coud be ok, or maybe place your straping on 12 OC.
Also I think for the purpose of breaking the hydrolic presure issue thinner straps could be used .. say 1/4 lath sticks. then you could easily add layer of 1/2 plywood onto of them to support the metal lath.
Also what detail would you use at teh top of teh stone to allow the air to flow out, just flashing out over the top of the stone cap?
Exterior faux rock spanning dissimilar materials
Yes, I was going to just go with flashing above the stone/rainscreen to provide for airflow.
Back in the olden days in Florida they just put stucco screen over the studs and laid on stucco for the interior walls (finished smooth). It made a very hard wall. I can't imagine a ball hurting that. If you did something similar it would be an excellent base to put the stone on. Are you talking about something like Eldorado stone? That will stiffen the wall up a lot too.
Since they used the same technique as tile base in showers, I doubt you will get that much water intrusion. If you use the felt backed wire, I bet you could skip the rain screen. The water intrusion seems to be around penetrations like doors and windows if they are not sealed up correctly.
Exterior faux rock spanning dissimilar materials
I am not exactly sure what kind of stone it will be, maybe something like Eldorado, maybe not, I guess my wife will tell me.
I appreciate your comment about omitting the rainscreen. I was thinking about that, especially where the rock would be applied to the foundation - what would be the benefit of rainscreen over peel and stick waterproofing over ICFs? Might as well screw the lath (metal mesh for mortar) right to the ICF connectors and go from there down to grade terminating the applied rock into 4" to 6" of washed rock at grade?
The benefits of a rainscreen are heavily dependent on your climate and environmental factors. For instance, my home has numerous bouts with wind driven horizontal rain every few months. A rainscreen is a good thing here.
That makes sense with siding but he is putting rock on what is basically a stucco mud base.
BTW to the OP, when we were looking at Eldorado stone, we ended up here
http://www.nsvi.com/
Real stone looks a lot better for a little more. It all depends on how close you get to it.
That stucco mud base or whatever concrete like material he chooses will be attached to a plywood or other wood based sheathing. If water gets into that point (and it's likely to in my climate), there is going to be rot. He could use treated ply as sheathing.... that would be helpful. But what about the studs? They'd need to be treated too and, for me, that's too close to where I live for chemically treated wood.
The flashing at the upper edge of the rock wainscoat is vitally important. The builder of my house apparently didn't know what flashing is. When I removed the rock on my exterior I also evicted some wet wood termites and swept and/or vacuumed up what was left of the stud wall. Not a pretty sight.
Soooo you suggest ...
Your experience is what I have heard about and fear.
It is interesting; however, that nearly every new house of any price point higher than the very bottom has some rock 'siding". Either there is alot o funknow damage out there or all is well or ..... Hmm?
That said, what are you saying or suggesting? Don't do it at all? Or, use a rain screen?
I think if I have any stone on my house I will either use one of these special drainage mats or I will have a double alyer of sheathing with an air space between. The latter might make the top cap on the stone difficult in that the top cap would have to extend out a bit more to accomadate the added thickness of the rain screen / sheathing.
They sell special mat ..
They sell special mats to act as vapor barriers to go behind stone which provide water to weep downard. Don't recall the name of it. Soemone here might know or google it. Sounds like a good idea if you don't do the rain screen.
I think you are right to be concerned about dampness behind the stone. Someone here was advicing that it was like stucco or a shower, well all I have heard is the OSB behind stone can turn to mush. That means moisture. And to me that means insurance is a good thing. Some kind of a break to make sure water is not forced into the sheathing.
If you use the stucco wire with the roofing felt backing and that is over Tyvec house wrap I am not sure how the moisture gets to the OSB.
Not Vapor Barriers
Tyvex and roofing felt are not water proof. And rock and especially the fake stone is not water proof either. In addition you will note that dry stacking veneer stone in an exterior application is NOT RECOMMENDED by manufacturers. And why would that be? Becaue water can more easily get behind the stone and ... what ..... wet the substrate? and or freeze thaw the stone off (not sure which is the risk). Lastly, there are horror stories, usually someone here will site one, where OSB under stone turns to mush behind the stone. Why would that be if tar paper or house wrap does the trick. And why would they sell these special mats to go behind the stone if tar paper were good at keeping water off the OSB? I suppose they sell it to scare people into spending more money... perhaps?
I talked in passing with a framer recenetly on a different subjecta nd he came around to some related issue and said "you can 't put stone on OSB only plywood"? Did he know what he was talking about? Don't know but he must have had some experience with it.
I am not sure what to think, but I sure know I would want this detail done right.
Food for Thought?
Must be a northern thing. I am sure you are right but I see that stone everywjere here although it is over block..
I see it all the time ..
I see it all the time as well, it is the FAD. ANd I guess most of teh time it works out well enough, but why to some say it is a accident waiting to happen or don't do it on OSB? ?????????????
Up in Atlanta I saw stucco over wood everywhere. The problem that some builders were getting sued over was in the penetrations, not out across the wall. Water was getting in around the windows and doors, eating up the wood.
Here in Florida we don't really see that much stick built construction. By the time you buy and install all the Simpson connectors that the wind code requires, you might as well lay block. Most of the wood you do see in window and door bucks is PT.
Steel studs are very popular for interior framing.
Exterior faux rock spanning dissimilar wall material
Hello Sapwood,
Thank you for your reply. Okay, I will work on it and load a drawing to help with accurate visualization.
stupid ad choice ad blocks last post!!!!!!!
I could SWARE, but was reminded that God cares so I will live it to everyone's imagination.
Ask the manufacturer
Frequently, manufacturers have details for atypical installations. I'd say it's worth a call to talk with one of the faux stone engineers.