Burlington reader has heating questions

Burlington reader has heating questions

Burlington reader has heating questions

Henri de Marne (Photo: Courtesy photo )

Q: I have a question about locating an instant hot water boiler in an attic in Vermont. We own an up/down duplex in Colchester. We need to replace the hot water heater (gas) located in the basement, and the upstairs apartment has two of those Rinnai direct vent wall heaters for heat. They are sufficient, but not ideal for the higher-end look we are aiming for.

We are looking at installing a Rinnai tankless domestic hot water heating unit in the attic to serve the upstairs apartment, running forced hot water heating to the apartment, eliminating the direct vent space heaters and the water heater in the basement. There is already a plentiful gas line to the attic feeding a natural gas dryer. The attic is insulated on the floor, not the ceiling, and has soffit vents and one gable vent. The attic is about 900 square feet.

My plumber is concerned that the attic will get too cold in the winter, and despite the instant water boiler’s systems for preventing freeze-ups in the boiler, the pipes feeding the radiators/domestic hot water systems may still freeze.

What would you recommend to alleviate this concern? Insulate the roof? Close all vents during winter? Dehumidify the attic? Establish a warm instead of a cold attic? Create an insulated area of the attic for the boiler and extra insulation for the pipes outside that area? I haven’t monitored the area, but it would seem odd that the temperature wouldn’t be at least 40 in the attic, even in subzero winters with the wind blowing. Unfortunately, there is no realistic solution for locating the boiler in the living space, or eliminating the need to run the heating pipes in the attic. Many thanks. — Burlington, Vermont, via email

A: Not only do I recommend that you listen to your plumber, but you should also know that installing a heat source in an attic will cause the snow cap to melt and result in ice dams and potential damage to the building. This happens even in attics without any heating sources from just the heat loss from the lower conditioned space.

Years ago, I was called in by a builder in New Hampshire who had installed a similar system in the attic of a house she had built for a client. Huge ice problems developed.

Because of the difficulty of relocating the heating system elsewhere within the conditioned space or the basement, we tried insulating between the rafters with foam, stapled a reflective barrier to the bottom of the rafters and increased the attic’s ventilation without success. We then built a heavily insulated tentlike structure over the heating system, including all ducts, with a fan in one gable and an exterior air intake in the other to remove as much of the heat from the tent as we could — all to no avail.

It sounds as if you may need to keep what you have (Rinnai heaters are found in many places), or work out a way to run pipes from your new heating system located in the basement throughout the entire building on separate zones. If your plumber is fully licensed, he or she should be able to come up with a solution.

Q: My house is a raised ranch built in 1973. What makes it somewhat unusual is that it has steel floor joists. Would the remedy for squeaky floors be the same for steel as for wood joists? I haven’t come across anyone that has worked with steel joists. I would hate to wait to install new flooring to try to add screws from the top as I do have access from below. I would greatly appreciate any advice. — Elk Grove Village, Ill. via email

A: I assume that the flooring includes a plywood or particleboard subfloor and a finished flooring material.

You need to determine if the squeaking occurs because of a separation between the subfloor and the finished floor or between the steel joists and the floor system.

Since you have access from below, ask someone to walk on the floor while you investigate from the basement or crawl space.

If you see that the subfloor is solidly attached to the steel joists and there is no movement, the squeaking must be taking place between the subfloor and the finished floor.

You will need to determine the thickness of the subfloor — probably ½-inch to 5 /8 -inch — and of the finish floor, which could be 25/32-inch if it’s strip flooring.

Use flat-head wood screws that will be shy of the depth of the floor system and have a smooth shank below the head before the threads start. Pre-drill holes of the screws’ diameter up through the subfloor only. Using a smaller bit, continue pre-drilling holes partially into the finished floor, being careful not to go through it. Then use washers to prevent the screw head from digging into the subfloor, and tighten the two members together wherever you observed squeaking.

But if the squeaking occurs because of a separation between the steel joists and the subfloor, you will have to drill holes in the top flange of the steel joists and, using the appropriate size screws, draw the floor system tight to the joists.

It may be wise for you to hire an experienced carpenter to do the job.

Q: We have an addition that was added to our home 35 years ago. The builder at the time used plywood at the corners and a black fiberboard on the rest of the house. Over the years, several areas in the house have seen increased cold spots. I have caulked, added ridged foam insulation and “Great Stuff” foam to the rim joists in the crawl space, used foam shields in all the electrical boxes and tried tightening up the house as much as I could.

After this last super cold winter, I called an insulation contractor to inquire about injectable foam, but after taking off some of the aluminum siding and drilling some inspection holes, it was determined that the walls have adequate insulation and would not be a candidate for the foam.

Part of our house was re-sided with vinyl siding 20 years ago, at which time they installed ¼-inch foam board under the new siding. It was suggested that replacing the aluminum siding on the “new” addition could possibly help to tighten up that portion of the house.

I have contacted a siding contractor and have been told they will remove the aluminum siding, wrap the house in Tyvek taping all seams, install 1/4-inch foam board and install the new siding. In addition, we will be replacing all of the old windows and the areas around the windows will be injected with foam, and then the sills will be wrapped and capped.

One area of most concern is the fireplace and raised hearth. The fireplace was a metal modular unit with an outside air exchanger put in when the addition was built. The raised hearth is a plywood box covered with the “Z-Brick” type of fake brick. The hearth and the area around the fireplace are extremely cold to the point of us hanging a quilt over the fireplace during the cold spells. The insulation contractor said the space in the hearth is too big for injectable foam.

I would like to get your opinions as the best way to seal the addition when they put on the new siding and windows. Will the Tyvek and foam board help? I would also like any suggestions on how to insulate the fireplace and raised hearth, since I might get access to it when they remove the siding from that wall. Thanks you for your help. — Naperville, Ill. via email

Burlington reader has heating questions

A: Instead of ¼-inch foam board, which adds only a minimal R-1.25 while air-sealing — which the Tyvek does anyway — I suggest that you use 1-inch thick XPS (extruded polystyrene) to gain a substantial R-5.4.

I think that the best way to determine what to do to make the fireplace more energy-efficient can only be done as you get into it and see why it is so cold.

Q: My question has to do with a burn on my part solid wood/part veneer table. I put a hot dish from the oven onto a hot pad that was not sufficient to keep the heat off the table. I have a large white mark and a couple little splinters where the heat split the wood.

Could you please advise me if it is possible to repair the burn and if so, how to do it?

Thanks in advance for any help you can give me. We enjoy your column and the knowledgeable advice you give. Thank you. — Essex Junction, via email

A: The white mark is an indication that heat and possibly moisture have damaged the table’s finish. This white mark can sometimes be repaired by rubbing the mark with white toothpaste, an abrasive that will remove the finish and leave an indentation. The appropriate new finish will need to be applied to fill the indentation — a tricky job.

You can also try rubbing the spot with butter, an old trick I read about in a book by a famous French antique furniture restorer. But this will not repair the finish.

The splinters are another story. The best way to deal with both problems is to have a furniture restorer/refinisher take the table to his/her shop where the repairs can be done, using the needed chemicals.

Q: My question is about tinting windows. My house is in Chicago and I would tint the windows on the east, west and south sides of my home.

Due to “blocking” the sun, would I be saving money with ComEd in the spring/summer just to give it back to Nicor in the fall/winter? — Chicago, via email

A: Window films are a very good investment. They lower the glare and considerably reduce the damage caused by the ultraviolet rays of the sun on furniture, furnishings and fabrics while reducing heat transmission. This may minimally increase the need for heat in the winter, since they will diminish solar gain through the windows, but they also help reduce air conditioning costs in the summer — a more important factor.

We had 3-M films installed on all south-facing windows and a skylight, and have noticed a great difference in comfort and glare.

Send questions to henridemarne@gmavt .net, or to First Aid for the Ailing House, Universal Uclick, 1130 Walnut St. Kansas City, MO 64106.


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