Block wall construction, exterior questions.
Hi, I'm new to the forum, and have several questions about a 'tumbled' block wall I am going to construct outside. I bought 75 (plenty) of 12X8X4 'tumbled' blocks to build a mostly non retaining freestanding wall at the edge of my back patio. It will be 24" high, 9'-6" long, 8" (block width) wide. This is 6 courses high. The following are my questions, and your expert advice is much appreciated:
My idea to do this started when I saw a 'kit' from a home improvement store for a tumbled block seatwall. It was overpriced but came with all the blocks precut, plans, masonry grade adhesive, gloves, etc... So I just bought the individual blocks and I'll figure out the rest... So, question #1,
1. The kit is 5 courses high and the blocks are masonry adhesived together, no mortar. I understand that this is probably fine for 5 courses, but I'm going six, and my wall is longer than the 'kit' wall (which was 6'). I plan on mortaring (type S) the first course to the patio for sure, and then masonry adhesive the rest of the courses. Will this have a bad appearance, and should I only mortar the bottom of the blocks and not between the blocks, since the upper courses won't have mortar between them? Or should I mortar the entire wall?
2. The blocks have a 'dry stacked' look, so I'm afraid mortaring the entire wall would give it an undesirable appearance. Am I correct in this opinion? This kinda goes along with question #1, and is another point for mortaring only the first course.
3. The patio is sloped 2" from the house to the edge, for drainage purposes, along what is going to be the length of the wall, therefore the wall will also be 'out of level' across its 9'-6" length as well. I don't think there is any real way of remedying this, and I don't think its a big problem. Any suggestions here?
4. What is the most effective way to split the block? I will need to split/cut several blocks into 1/3's and 2/3's, to create the desired appearance of the wall. I have a concrete saw (stihl chainsaw looking type with concrete blade). Do these blocks need to be cut all the way through with this saw, or do you score them and split them with a chisel, or something else?
5. Will slicing them all the way through with the saw give them too much of a flat straight edge on the cut side to look poorly when incorporated into the wall of blocks whose edges have a rougher and softer appearance?
Thats all the questions I can think of for now. Thanks for reading all of this and I look forward to your expert correspondence.
Anyone have any answers for maybe one of the questions?
Sounds like you are using concrete masonry unit (CMU) blocks dry stacked. Most of those walls do not require adhesive, I am not quite sure why you are using it, maybe a picture would help. I built a similar type retaining wall in my backyard, stacked four high, no adhesive, but if you are building a freestanding wall perhaps the manufacturer recommends adhesive to keep the blocks from shifting. My blocks have keys that prevent shifting.
As for cutting block, you can score them about 1/4 through using a diamond blade and a circular saw, then tap them with a small sledge, and they cut pretty clean. You can also saw all the way through, but not necessary. I cut several of my blocks that way, couple of things to consider. Make sure you use a NIOSH dust mask, concrete dust is VERY bad for your lungs. Use eye protection. Use a diamond blade, the carbide blades do not last long and are not worth it, diamond is cheap and very effective.
As for the use of mortar, if you have CMU retaining wall blocks, you should not need mortar. If you do not have retaining wall blocks, the manufacturer should include construction guidelines with the block, and perhaps you need adhesive or mortar.
As for the out of level question, I don't understand your plan. Walls are generally built level and plumb, unless there is some overwhelming reason to deviate. In your case, if you building the wall level, then perhaps you need to vary the total number of blocks from one end to the other, but of course if the bottom is level the top will be level if you use a consistent number of blocks. Or maybe I do not understand your plan.
Thanks for your reply.
I am not using CMU blocks. These blocks are more like retaining wall blocks. Here is a picture:
I think your method of block splitting will work. I will try that.
The wall would be out of level along the length because the patio is out of level by about 1 1/2", because it is sloped, from the house to the patios edge. This is for water runoff.
So I guess I'm still wondering about mortaring it all together, or masonry adhesiving it all (except the first course which I plan to mortar).
Unless I'm completely off on my calculations your 2 ft. wall will only be off vertical from bottom to top by 0.2" if the patio slope drainage is 2" and the patio wall is 20 feet from the house.
If this is too much is there any reason the first course can't be made level by adjusting the mortar bed?
I must not be explaining the slope very well, for that I apologise. The wall starts at the house and goes to the end of the patio. Hence it will slope exactly as the patio slopes, which is about 1 1/2". The patio slopes 1 1/2" from the house to the edge of the patio, so the wall will too, unless I try and remedy this.
So my question then would be: If I slope a bed of mortar on the patio to bring the wall to level along it's 10' length, and I have a 2" mortar line at the bottom of the first course that gets narrower the closer I get to the house; and at the house that mortar line being reduced to just a 1/2", will that
A. work?, and B. look stupid?
And THEN, should I mortar the ENTIRE wall, rather than use masonry adhesive on the next 5 courses?
And if I mortar just the bottom course, should I then refrain from mortaring BETWEEN the blocks, and do only the bed/bottom, so as to not look different from the courses above, which would have no mortar between them because they would be adhesived?
I would recommend making the wall just outside of the patio, bearing on solid ground, and then making it level. Your idea of using mortar is less than ideal, and it's going to be harder to achieve than it sounds.......
Yes, thank you for the reply.
I realize that leveling the wall in a bed of mortar wouldn't be easy, but I'm willing to give it a shot. I think I will make a small form for the mortar bed to sit in before I place the blocks. Putting the wall outside of the patio isn't really an option. The patio at that side is also a footer for this wall, which I planned in advance of the patio being poured.
So, for the sake of argument, I COULD mortar a bed for the bottom course, and also make the bottom course level with said mortar bed, then my question is: Would the mortar bed hold the weight of the wall fully constructed?
That might be a dumb question, but I don't know if a 2"-2 1/2" bed of mortar would 'crush' beneath the weight of the wall or not. (wall is 6 courses high, about 2'.)
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