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We are trying to find the best way of using natural stone to face a timber frame house. Because of the plentiful rain here in Ireland there must be a 50mm (2 in.) gap between the timber frame sheathing and the stone face. The stone will only be going up one floor level. We will be using stainless steel ties to link the frame with the stone. What we would like to know is what is the best way of putting up the stone and maintaining the gap? Most people here put a 100mm (4 in.) block wall up first (to create the 50mm gap) and then face that with the stone. It seems wasteful to me to do it this way but perhaps it is the best way to do it. By the way the stone in question is sandstone.
Eugene.
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Hi Eugene,
It's common here to install most dimentioned or cut stone with a gap of 25mm and even 50 mm is not a problem. If your stone is rubble or irregular in depth then you will have a problem in maintaining consistent separation.
This may not be acceptable in Ireland and would have to satisfy your local authorities.
Structurally, I can't think of any reason why you couldn't but it's not up to me.
Gabe
BTW, nice to welcome you here.
*Eric,Personally I would install 50mm thick high-density polystyrene foam sheet behind the stone which will help maintain the straightness of the wall and add insulation. A cavity tray at the bottom of the stone and weep-holes in the first course are essential anyway and as sandstone is quite porous I'd finish it with two coats of silicone liquid.I have installed 20mm thick marble this way, using the same sort of SS stand-off anchors, with no problems.If the stone is not regular in thickness, or you don't want to use the polystyrene, then plumb up profiles at each end and fix the stone to a string line pulled between the profiles.
*Gabe,Thanks for your reply. The stone is random in size so as you say this leads to the problem with mainitaining a consistant gap. One possibility is to hire a stone cutting sawbench and get a smooth cut face on the inside, leaving the natural uncut face on the outside. This would also allow a fairly consistent thickness to be achieved. I don't know how easy is is to use such a saw but we have quite a lot of stone that is on the large size (left over from doing a drystone retaining wall) and it would do no harm to reduce it.Eugene.
*Ian,Thanks for your suggestions. I am interested in what you had to say about drainage. What we had in mind was to bring the stone wall down further than the timber wall i.e. if the timber is sitting on two blocks then start the stone on only one block. Does this sound adequate?We are trying to avoid polystyrene and other synthethic materials where possible (the main exception so far being underfloor insulation but I am still looking for alternatives). The frame itself is oversized to allow for very high insulation levels - the studs are 225x50mm (9x2in)and will be filled with cellulose insulation. Somebody suggested using a sheet of polystyrene but moving it up as the wall rises. This way the SS ties cannot be applied until the polystyrene sheet has been removed but it does create the required gap.Eugene
*Eugene,Sandstone that I've played with can be cut with chisel/hammer and would be easier to do yourself with a little practice. Stone has a grain just like wood and you have to train yourself to read it.Take a small piece and whack it with a hammer dead center. When it breaks, look at the fresh sides and you will start to see a pattern difference between a cross grain cut and a slice along the grain. Compare the pattern with what you see on the outside raw stone. You should start to see a basis for the grain direction.This is what you use to determine the way you cut stone so that you just don't shatter all the stone into little useless bits of rubble.Always try to cut along the grain.Let me know if you try this.Gabe
*Eugene,I would still add the cavity tray, it may be 'belt and braces' but the extra work is worth it. Don't forget to clean off the mortar droppings as you go.When you say the stone is random in size, I presume that it is rectangular but random in thickness.As long as the 50mm gap is left between the back of the stone and the timber frame, irregularity won't matter.As I said before, plumb up a profile at each end of the wall to work with and pull string lines to set the front of the stone.Make sure there is a good mortar joint between each stone and you may find it easier to lay the stone 'brick pattern' as the attached photo as it means you don't have to worry so much about keeping the bed joints level, you've only the vertical joints to keep straight.Still go with the silicone liquid or similar to waterproof the wall after you've finished to prevent damp penetration.
*Gabe,The problem is that I will have to go cross grain as well as with the grain as the stone is on the large side in all directions. But it might be best to manually split with the grain and mechanically cut when I go cross grain.Eugene.
*Ian,The stone is actually completely natural i.e. random everyway. However it has some good natural flat sides as it tends to break that way.It seems like the string lines then are the best way to set up the alignment and maintain the gap, simple but should be effective. I will take heed of your suggestions regarding drainage.Eugene.
*Eugene,If I understand from your last post that the stone wall will be built from randomly shaped pieces of stone -- rather like 'crazy paving' then you most certainly do need a block backing wall.In a normal wall any settlement/movement is along the joints -- to a certain extent that's their purpose -- with random and irregular joints there's too much risk of movement resulting in the whole wall buckling.I would only build this unsupported by a backing wall if the stone were 150mm thick at least.
*Ian,I should have said that for the reason you pointed out we will have to keep the stone fairly thick. Do you think 200-250mm thick would be enough for a height of 2.4m? Naturally I would like to keep it at the lower and of the scale.Eugene.
*Eugene,The important items are keeping the joints regular in width and the edges of the stone trimmed square.200 - 225mm should be adequate for a wall that height. Look at the cost implications between a 100mm block wall with 50mm stone cladding and a stone wall 200mm thick, it may be that the cladding will be cheaper. I presume that you will be building this yourself.
*Ian,We are using stone from a local quarry but they have no facility for cutting so we get pretty big stuff. But, if hiring a saw and cutting 50mm thicknesses is viable, then the block wall+stone could be the answer. Picked stone costs about $23 a ton delivered so in thin sections a ton would go a long way. In any case my wife and I would do the less skilled work while somebody with more experience will do the actual wall build.Eugene.
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We are trying to find the best way of using natural stone to face a timber frame house. Because of the plentiful rain here in Ireland there must be a 50mm (2 in.) gap between the timber frame sheathing and the stone face. The stone will only be going up one floor level. We will be using stainless steel ties to link the frame with the stone. What we would like to know is what is the best way of putting up the stone and maintaining the gap? Most people here put a 100mm (4 in.) block wall up first (to create the 50mm gap) and then face that with the stone. It seems wasteful to me to do it this way but perhaps it is the best way to do it. By the way the stone in question is sandstone.
Eugene.