Building short cinder block fence

[saidiasikh]

<edit: clarified some q's, added new ones>

Hello, I need to install a gate in our driveway and have decided to build a very short cinder block fence on each side of the metal gate (I.e. 2 pieces of fence seperated by a gate) Each piece will be 4 bricks long (each brick is 16" by 6"). Height will be 6 feet. I'm used to doing DIY projects (replumbing house, some electrical, drywall, etc), but this is my first attempt at building a Cinder block fence :-) Will be using a hand mixer (probably just a tub and a 2x4)

Some questions:

- Simple Q first - How do I cut the blocks? If I use a chisel, how do I smooth out the cut edge? I read somewhere (cant remember where) that the blocks could be sawed with a hacksaw - is this true? If so, is it easier to go this route for such a small job?

- How deep/wide should the footer be? Can I get away with not using wooden forms and just dig the hole wide enough for the footer?

- Installing the rebar - I saw the article on concrete footings on this website. How do I tie the vertical rebar to the horizontal rebar? Do I need to bend it? How?

- I realize that I will be filling in the hole in the cinder blocks with the rebar (using concrete), do I need to fill in all the holes?

- Do I use concrete as mortar? If not, what should I use?

- Some of the cinder bricks have holes in the side (horizontal rebar?) What are these for? If they are for Rebar, how often do I need horiz rebar for a 6 foot fence that is not load bearing?

- The footings on each side will be perpendicular to the existing concrete driveway. What kind of concrete do I use for the footer? How do I "bond/join" the concrete (of the footer and the driveway) together? Drill holes in the side of the driveway and use concrete anchors? Do I need to bond the pieces together?

- The bricks will start just below the height of the driveway (to match the fence next to it (see below). Should I chisel out a few inches from the top of the driveway to line up the base cinder block row, or should I build a base of concrete on TOP of the driveway portion and start the bricks level with the 2nd row of adjacent fence? If I build up the base using concrete, do I need to add rebar to the portion over the driveway? How do I tie it into the driveway TOP?

- One wall will end perpendicular to an existing cinder block fence. How do I join these? Concrete anchors? L bracket? What kind?

- Other wall will end perpendicular to the external stucco house wall. How do I join these? Do I need to find the studs in the wall to anchor the fence to the studs?

Thx for your help!

[Rich]

I don't have time right now to answer this but will get back to you as soon as I can.

[Rich]

- Simple Q first - How do I cut the blocks? If I use a chisel, how do I smooth out the cut edge? I read somewhere (cant remember where) that the blocks could be sawed with a hacksaw - is this true? If so, is it easier to go this route for such a small job?

There are several ways to cut the block - some are better than others. I would recommend a standard masonry blade in a circular saw.

- How deep/wide should the footer be? Can I get away with not using wooden forms and just dig the hole wide enough for the footer?
I would say at a minimum 24" wide and 8" deep. The reason I say 24" wide is that when the gate is open there will be quite a bit of overturning moment right at the base of the wall. It doesn't take much weight to get quite a bit of force on the wall. Wooden forms are not needed but do consider the elevation of the footing. It should be below grade by about 4" so enough dirt can go on top of it to grow grass or whatever type of landscaping is going to go in there.

- Installing the rebar - I saw the article on concrete footings on this website. How do I tie the vertical rebar to the horizontal rebar? Do I need to bend it? How?
No need to bend it. As an aside - just need to clarify.. by cinder block do you mean concrete masonry unit (CMU)? I'll assume that's what you are suggesting.
Just use tie wire. With a concrete block wall you should have a course of bond beam blocks at the top, and in your case, one in the middle where the horizontal rebar will go. Bond beam blocks can be seen here (http://www.kingsmaterial.com/images/cm_standard6.jpg) in the second row down.

- I realize that I will be filling in the hole in the cinder blocks with the rebar (using concrete), do I need to fill in all the holes?
In your case I would suggest that you place rebar at a maximum of 4' o.c. Lay these out for your first course of block and they should line up for the rest.

- Do I use concrete as mortar? If not, what should I use?
Use a grout mix which is essentially concrete without the large aggregate.

- Some of the cinder bricks have holes in the side (horizontal rebar?) What are these for? If they are for Rebar, how often do I need horiz rebar for a 6 foot fence that is not load bearing?
See above answer

- The footings on each side will be perpendicular to the existing concrete driveway. What kind of concrete do I use for the footer? How do I "bond/join" the concrete (of the footer and the driveway) together? Drill holes in the side of the driveway and use concrete anchors? Do I need to bond the pieces together?
I would not tie the two together due to the fact that a footer and a slab will heave differently during freeze/thaw cycles. If you do tie the two together it could cause damage to the driveway.

- The bricks will start just below the height of the driveway (to match the fence next to it (see below). Should I chisel out a few inches from the top of the driveway to line up the base cinder block row, or should I build a base of concrete on TOP of the driveway portion and start the bricks level with the 2nd row of adjacent fence? If I build up the base using concrete, do I need to add rebar to the portion over the driveway? How do I tie it into the driveway TOP?
This is more of an aesthetic thing so whatever you want to do is fine. But as stated before if you tie into or on top of the driveway somewhere you will eventually have some cracking.. either in the wall or in the slab. I would suggest going below the driveway and end right at the edge of the driveway.

- One wall will end perpendicular to an existing cinder block fence. How do I join these? Concrete anchors? L bracket? What kind?
Lay out on the existing wall where the new wall will end up at and saw cut just inside of that line. Then run your horizontal rebar into that space and full grout it.

- Other wall will end perpendicular to the external stucco house wall. How do I join these? Do I need to find the studs in the wall to anchor the fence to the studs?
If you get really lucky and a stud lays out right where you are placing the wall then I would nail a pressure treated 2x4 on there. This should line up to be inside the wall itself. Then all you have to do to tie it in is knock out a small portion of the center of each end block and grout it in.

Hope that helps.

[saidiasikh]

Many thx for your help! Will start on the project in early Aug and let you know how it turned out! Thx again for this valuable resource - it's a cool site and you folks are quite responsive :D