August 28, 2011 in Features

Before you start digging your holes, dig into research

Gene Austin McClatchy-Tribune

Q. I want to put several posts in my backyard to erect a 6-foot privacy screen. I want to set the posts in concrete for strength. How do I go about this?

A. There are a couple of things you need to know before you start digging holes in your yard.

One is the depth you will need to go to get below the frost line – the depth to which the ground can freeze in winter. You can get this information by calling building-code officials in your municipality.

In my area, where winters can get quite cold, posts must be set at least 2 feet deep, although many contractors go to 3 feet.

The second thing you need to know is whether there are any buried utility lines in the area where you want to dig. To find out, call 811.

If you are digging only a few holes, the usual tools are a clam-shell post-hole digger and, if the soil is rocky or hard, a heavy digging bar to loosen the soil. People who want to dig a lot of post holes can rent a large gasoline-powered auger.

A clam-shell digger can be bought at most home centers and hardware stores for about $20. It has two long handles and two sharp blades. The blades are jammed into the soil and the handles are spread to pick up some soil.

Eventually you can dig a neat, round hole up to about two feet deep; after that, it is very difficult to spread the handles enough to pick up much dirt.

You should use 4-inch-by-4-inch pressure-treated posts suitable for ground contact. If you buy 8-foot posts, you can sink them 2 feet and have 6 feet protruding.

Put a little gravel or a few small rocks in the bottom of the hole before putting in the post, then pour in some dry concrete mix and tamp it down. Make sure the post is plumb (perfectly vertical) by placing a level against two adjacent sides.

Fill the hole with dry concrete mix, then pour some water over the dry mix. The concrete will harden and keep the post in position.

Q. There is a dark water stain on our hardwood floor where I used to have a plant. It is an older floor and I think it is finished with varnish. Can you help?

A. Dark or black stains generally mean that water has penetrated into the wood. These stains are sometimes difficult to remove, but bleaching sometimes works.

Start by putting a wide belt of masking tape around the stain to protect the rest of the flooring. Sand the stained area with 150-grit or 200-grit sandpaper, which should remove remaining varnish from the surface. Wipe off the sanding dust.

Moisten a sponge with full-strength white vinegar and wipe it over the stain. Wait several minutes, keeping the stain wet with vinegar. If the stain fades, continue vinegar applications, each followed by a wait of several minutes, until you are satisfied that the stain is removed.

If this doesn’t work, make a 50-50 solution of chlorine bleach and wipe that on the stain, repeating the sponging and waiting if the stain fades.

If this still doesn’t work, check paint stores for a small bag of oxalic acid. This is a strong wood bleach and you should wear rubber gloves, eye protection and long sleeves when using it. Mix a heaping tablespoon of oxalic acid in a quart of warm water and sponge it on the stain, repeating the system above.

If you succeed in removing the stain, sponge the area with clean water to rinse it, then dry it thoroughly with a towel or hair dryer.

Buy a small can of oil-based varnish that matches the luster of your floor. Thin some of the varnish by about one-third with mineral spirits (paint thinner). Remove the masking tape and brush on a coat of the thinned varnish. Try to “feather” the edges of the new varnish into the surrounding finish.

Let the first coat dry and apply one or more additional coats.

Q. I bought a house that has aggregate flooring about one-quarter inch thick in a couple of rooms. I would like to refinish the floors with tile. How difficult and expensive would it be?

A. Aggregate floors are epoxy resin impregnated with tiny pebbles, and epoxy resin is very tough stuff. I doubt that the aggregate can be removed without ripping up the flooring material under it.

It might be possible to install a new underlayment suitable for tiles on top of the aggregate, but this will raise the floor level slightly higher than your other floors. I think you should consult an experienced tile contractor and see if there are other options.

Questions and comments should be emailed to Gene Austin at Send regular mail to 1730 Blue Bell Pike, Blue Bell, PA 19422.

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