ranvic

Because of obstuction, I have to start a wall from two sides. Any ideas on connecting the corner first course, the two sides are 150' apart and 5' lower than middle corner, string line or laser level can not be that exact, using 8' high blocks. Thanks for your help.

concretemasonry

I really can't understand the situation. Where is the middle corner?

You will need a continuous concrete footing for regular block wall. Step footings are normally used for elevation chnages.

If you were using segmental retaining wall block you will not and cannot have a concrete footing. With this type of wall you step the compacted gravel base as needed (in increments equal to the retaining wall block height).

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Dick

AtlRemodeling

If you are building a MSE wall then start at the low point on one side, build up and over your obstruction in the middle and then work back down the slope (obstruction) to the low point on the other side.

It is a pain in the butt to work back down the slope but with a little patience it can be done and then everything will be at the same elevations on both sides of your obstruction. If the wall does not go over the obstruction, using a transit you should be able to get within an acceptable tolerance.

Kgmz

What do you mean a laser cannot be that exact?

I hope not or I have some pretty screwed up building sites the last 20 years.

We have done sites that are up to 2000' across, some over hills, around corners, etc. If for some reason you cannot place a laser and shoot all points of this retaining wall, you set hubs/stations and then move your laser so you can shoot the whole thing.