DEAR MR. MELTZER: We live in a nice old house, but it's really spread out and big. We have only one front door bell. So if I'm in the laundry room, bathroom, family room or any other remote room of the house, I don't hear it.

Is it expensive or difficult to have bells installed so that they ring all over the house?

ANSWER: No, it isn't difficult job.You can install additional bells or chimes to be heard in even remote parts of your house.

Installation of a new bell, buzzer or chime requires extending wire from the original bell to the new ones. First, you must turn off the current while you make the connections.

New wires are fastened to the terminals of the old bell. If you remove the cover plate, you will expose the terminals. Using the regular bell wire, strip the insulation off the ends of the wires, bend them into alight hooks, then loosen the terminal screws and slip the wires under and tighten them.

DEAR MR. MELTZER: I think my landlord is crummy, if not altogether a crook. I live in one of those renovated old town houses. My lease originally was for one year. After that, I was to go on a month-to-month. At this time, I am three months into my second year in this apartment. Yesterday the landlord sent me a registered letter, giving me 30 days to vacate. Shouldn't I be entitled to another nine months on my lease, since I've already lived here three months of the second year?

ANSWER: No, you are not entitled to another nine months. According to what you say, your lease specifically stated that after one year, you were to go on a month-to-month basis.

Therefore, your landlord is perfectly within his rights to enforce this provision of the lease. You'd better go out and look for another apartment.

DEAR MR. MELTZER: We bought a house that's 10 years old and it's beautiful. The only thing that shows wear are the formica counter tops in the kitchen. They are not scratched or marked in any way, but they're dull and old looking. Is it possible to put a finish on it, such as varnish?

ANSWER: Don't use varnish. Use an automobile wax, then rub and buff it generously. It will look fine, but it won't last permanently. You will have to redo it from time to time, depending on the amount of wear you give your counter tops.

DEAR MR. MELTZER: We have a hook-and-eye type catch on our sliding windows that seem to need a little perking up. Is this a difficult job?

ANSWER: No, it's a simple job. A level pivots on a points so that the hook can fasten onto a part of the window frame. Yours probably needs to be reshaped to get a hook back in functioning form. The easiest thing to do is to replace it, since most of these simply screw into place.

DEAR MR. MELTZER: My German shepherd has made holes in my screen door. How can I repair them?

ANSWER: You can patch screening either by shellacking a piece of mosquito netting over the hole, or by fitting a patch into place with lengths of wire similar to what is in the screen. In the second instance, you sew the patch into place, using the wire. Neither of these is a permanent solution, however.

Bernard C. Meltzer is a realtor, engineer and appraiser. His address: Suite 900, 112 S. 16th, St., Philadelphia, Pa. 19102.