Garden wall question.....

[chrisexv6]

The wife has enlisted me to build a small garden wall for her. The area is currently sloped (the top is our pool deck, the bottom of the wall is about 17" lower). The goal is to have the wall be level with the pool deck, and about 7' out creating a (rather large) planting area.

Ive done retaining walls before so Im comfortable with what to do, but this is the first one Ive done on a slope. My question is: as the slope goes upward towards my pool deck, do I "step" the blocks up, or do I have to dig out a full 17" deep the whole way around where the wall will go. I have plenty of blocks to do it the hard way (17" deep) but it just seemed senseless to me to be burying all those blocks as the distance to the pool deck height decreases.

Thanks in advance.

-Chris

[Bru75]

Stepping the blocks is ok as long as the sub grade is solid and you keep at least one block below the finished grade. It might be easier and faster in the long run to dig it out level. This way you won't have to worry about compacting and leveling every step, just one level.

[chrisexv6]

Thanks.

I actually started today and stepping wasnt as bad as I thought. Wasnt easy, but wasnt too bad.

It also helps that the minimum radius of the block took me into ground that was only 12" off from the pool deck instead of the estimated 16. Saves me one "step", and a bunch of blocks. Now I just need to figure out what to do with the extras :)

[betmr]

Is your footing going to be below the frost line ? I see your in Conn. Gets cold there ! It'll heave those blocks all over the place. Also, You did'nt say how old this place is, could it be fresh fill ? If your setting block, I would suggest setting on Virgin soil, if it's fill, you're gonna have lots of settling.

[chrisexv6]

Footing isnt below the frost line (42" worth of block for a 12" high wall? sorry :) )

I built a larger wall the same way a few years ago and it hasn't moved at all.

Its virgin soil, I cant get decent fill around me anyway :) couple people in my neighborhood carted in some fill and the comment was basically "its like pudding".

[chrisexv6]

Actually one more question:

I want to add drainage behind the wall, but Im not sure how.........since the wall "encloses" an area, whats the best way to get the water *out*? I was thinking perforated drain pipe, but wasnt sure if I can exit it out underneath the foundation of the wall (figured it would weaken the structure). I did this in another wall I built but the wall didn't enclose anything so it was easy to have the pipe follow right behind the wall.

Any tips/ideas?

[Bru75]

Put the perf. pipe behind the wall in about 10" of clean 3/4 inch gravel. It will need to exit at the low point through the wall at ground level.

[chrisexv6]

The exit part is my problem.

I cant leave a block out for the pipe to come thru: the blocks are only 6" wide, so Id have to leave out a complete block for the pipe to come thru, and there wouldnt be any support for the block(s) above it.

[mdawson]

The exit part is my problem.

I cant leave a block out for the pipe to come thru: the blocks are only 6" wide, so Id have to leave out a complete block for the pipe to come thru, and there wouldnt be any support for the block(s) above it.
Sure there is. You are staggering the blocks correct? So only half of the block on the next row would be "unsupported". But, in actuality, the pipe is rather strong by itself. 4" corrugated pipe or solid PVC should take some of the weight, but the remainder will be spread over adjacent blocks. If you want, you could add some cement around the pipe for more support.

[chrisexv6]

Thanks for the tips so far. I will leave out one block at ground level and let the 4" pipe exit there (it will be on the side you cant see, so its not a big deal).

Another question. The wall is roughly a perfect half circle. Im butting it up against an existing concrete slab. I started at one end, and got far enough when I realized that, since I want the wall to match the ends of the existing slab, I dont know exactly how many blocks need to be run straight, before I start curving into the other side of the slab.

To remedy this, I started blocks from the other side of the slab, figuring at some point I will meet in the middle, or at least close enough that I can start cutting blocks. Now the only issue I have is making sure each side will meet *level* in the center.

I put a laser level on the ground next to the wall (about 5' away). I then measured the height of the dot off one side of the blocks that are laid, and the same distance on the other side. The issue I have with this is that the dot gets "fuzzier" the farther away from the laser I get. Because of this, it looks like Im anywhere from 1/16" to 3/16" off from side to side. Keep in mind, this is a 20.5' distance. In construction it might not be a big deal, but when I try to have the blocks meet up it could be a big deal.

So, because of the laser "fuzziness" I tried a string level. This is what scares me: after putting a taught string between the ends of the wall, with the level in the center of the string, it shows Im about 1.5" off. Thats MUCH worse than 3/16", of course.

So, which do I trust? or can I not trust either and have to try another way ?

Thanks in advance.

-Chris

[betmr]

Rent or buy a sight level. It's like a transit level except it doesn't aim up and down. And as you lay those blocks, 1/8" gets bigger the further you go. And you have to get a string line really tight, to keep it from sagging in the middle. Just my thoughts on it.

[Bru75]

Your laser level, if it's a quality one and set up right, should be much more accurate than a string level.

[chrisexv6]

Thanks for the replies.

I will look into a sight level.......I figured there was something for the job, now I know what to look for. Incidentally, I figured since I was measuring at the far ends of the wall, any error I see would be the *max* error, instead of compounding upwards. I could be wrong on that of course.

I was using a Stanley "single point laser level" setup on the included tripod. I made sure the level was....level using the included bubble. At the point closest to the level I had a nice tight dot (about 1/16" diameter), at the point farthest it was fuzzy and about 1/8" diameter. Im guessing this isnt a "quality" laser level. Im not sure where to rent a good laser/sight level, any ideas? I dont know if HD rents that stuff (might be worth a call, figure someone has to rent this stuff for people installing walls and such)

-Chris

[Bru75]

You should be able to find somewhere to rent one. The problem with those lasers is that if the bubble is off only slightly it will be more and more off the further away from it that you go. My laser is self leveling and accurate to within 1/8" over 100 feet, kind of hard to make a mistake with it. If you have a friend in construction you might be able to borrow one or just have them stop by to check the level of your base.
Hope this helps.