Finished Basement Heating Requirements

HitzKup_2

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CPyne

Finished Basement Heating Requirements

Hi,

I'm in the planning stages for how I should finish my basement. I'm wondering if anyone has any suggestions on heating requirements.

Here are some details on my house...

Built 1959. 1500 SF footprint. Roughly 900 SF would be finished in the basement. Upstairs is heated via boiler and baseboard radiators.

First, do I need to heat the basement provided I insulate the walls well? (I'm in Massachusetts).

If I do need to heat it, am I better off adding a second zone to my existing boiler or would it be more cost effective to go with electric baseboards?

If I was going to add another zone to my boiler, any thoughts on if it would be able to handle the additional load? (see attached pics)

Any other advice would be great.

Thanks
Charlie

Tom Hopkins

Why?

Why finish a basement around that Dinosaur?Put a Mod/Con in there and put a major dent in your fuel costs.A mod/con on an outside wall will free up space,eliminate the chimney,provide sealed combustion,superior DHW with an indirect etc.
Why build around that relic?

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Steamhead (in transit)

Charlie, the first thing to do

is a heat-loss calculation on the whole house. This is far easier to do now that we have computers- you can click on "Heat Loss Calcs" above for a free program from Slant/Fin that will run on any computer using Windows 98 or higher. If you have dial-up, the download will take forever- order the CD instead.

Once you know the heat loss of every room, including the basement, the "job totals" will tell you if your old Hydro-Therm will handle the extra load. The Net load is 93,000 BTU per hour (620 square feet times 150 BTUH/square foot) so your total shouldn't be much above 93,000 BTUH with 70 degrees inside and whatever the outside design temp is in your area.

Also, I'd consider replacing that boiler. It's not that efficient- I've never seen an old Hydro-Therm that could exceed 70% combustion efficiency or so. If a mod-con isn't the answer in your house, a wet-base boiler that can fire with gas or oil will be more efficient than a standard gas boiler, and could switch fuels if the gas utility gets too greedy.

I wouldn't use electric baseboard. It's way too expensive to run these days.

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Mike T., Swampeast MO

Be very careful and do significant research before insulating exterior masonary basement walls in old homes. It's EXTREMELY easy to set up ideal conditions for "dry" rot, termites and other damaging insects! The exterior of the walls is truly the only proper place to insulate unless you take finicky measures to ensure ventilation behind the finished walls. Even rigid insulation requires such measures. I've torn out finished walls in the basements (some insulated, some not) of many old homes and have ALWAYS found rot, mold and very frequently termites as well. Personally I think the best finish for such walls is plaster--high Portland cement with solid or block cement walls; high lime with brick or stone.

Also don't forget that the basement ceiling generally offers the best access for any changes or improvements. Electrical junction boxes should never be covered by a "permanent" ceiling and water leaks/accidents are inevitable. While not especially attractive and somewhat "headroom hungry" I personally believe that removable ceiling panels (e.g. "drop" ceilings) are the only ones appropriate for a basement. Even with removable ceilings, evidence of termites (while often hard to see early even when everything is open) will be completely hidden until SEVERE damage has occurred.

Tom Hopkins

I face the same issue. Any thoughts on whether plastering the basement walls (leaving them exposed to prevent mold, but uninsulated) would be terribly enegy inefficient with a hot water system? I'm thinking that a heat source (either fintube or radiator) sitting next to an exterior wall that never gets above 50 degrees would just dissipate the heat rapidly.

Mike T., Swampeast MO

I've seen some articles in Fine Homebuilding and someone here once posted a link to a very good website regarding insulation/ventilation of all sorts but I can't recall the name and lost the link. Perhaps they'll re-post. Believe it was something .org

My local climate (Southeast MO) certainly influences my statements and enhances the problems, but the things I've read say the same problems occur through most of the continental U.S.

It's those cold, massive walls that tend to change temperature very gradually that cause the problem. When exterior insulation is impossible (nearly every renovation and not even a simple detail in most new construction). What seemed to be the "best" method I saw was metal studs, rigid insulation and finshed wall on the outside of the studs and continuous ventilation slots very near and along the bottoms and tops of the walls. This gives insulation only to the finished wall itself while still allowing natural ventilation in the gap behind.

High lime plaster is recommended for old brick (and stone like sandstone) foundation walls because it's somewhat vapor permeable--just like the brick. Use too much Portland cement and it becomes nearly waterproof and hydrostatic pressure will cause the plaster to "pop" off the walls taking some of the brick with it...

D107

Mike I think BuildingScience.com offers some detailed

diagrams and specs for insulating basement walls from the inside in their publications--some info free on their website. They have different books for different climates.

Re: your basement ceiling comment, one of the things I'm planning to do someday is to remove finished ceiling and after re-piping etc, fill space between joists with white painted sheetrock--recessed up into cavity to create a beam ceiling that will look nice and allow easy maintenance. This may have the added advantage of raising the height of the sans-sheetrocked ceiling enough to qualify for legal habitability--if you wanted to make a bedroom down there--and were very close to the 84"H I think at least New York State requires.

David

CPyne

Thanks Everyone

Thanks Everyone. I didn't want to have to replace this boiler since it "works", but I couldn't agree more that building walls around something this old is probably a bad idea. I'm glad for the input.

Regarding "Mod/Con" boiler, is there any good guide on the pros/cons? What should I expect to spend on one vs a standard gas boiler?

I actually have a copy of that Fine Homebuilding with the Mold Free Basement article and I plan to follow it in detail. This basement was finished, (badly), in the 70's and it developed some mold issues. I've never seen water on the floor, but this shows that if the fishing isn't done right, you're still asking for problems. I'll check out the Building Science site as well.

Thanks
Charlie

Mike T., Swampeast MO

Yep! That's it. www.buildingscience.com Here's the search results of "Basement Insulation"

While it's never fun to fit something rigid between existing joists, your idea sounds fine and reasonably attractive. Since the code required "headroom" specs I've seen are based on some percentage of clear headroom above some level, I have a feeling that your solution would meet the letter of the law, if not quite the true spirit...

laurence salvatore_2

basement

I would put radiant tubes over insulation on the old floor then pour a new floor over it. It would mesh well with your new heating plant. As for the walls, put up metal studs and hang some of the new 4'x 8' sheets of PVC which are available now. The sheets come smooth, shiplap, and beadboard (at least that I've seen so far). Then use 5/4" PVC for the baseboards with any of the miryid PVC molding available. The aluminum an PVC will make you water proof up to four feet as the 4'x8' PVC is usually installed long side down. A PVC chair rail, then some sheet rock and you are all set. Before you pour your new floor, dust your joists an anything else above your head but below the first floor; then spray it with white paint. Everything your wife wants to cover with that dropped ceiling or sheetrock will disappear and you will have a much more open feeling room and happy tradesmen in the future. The white paint really works try it before anything else. As for any lally colums or low pipes wrap them tighitly with rope thats 3/8 to 7/8 in diameter.

lee_7

there is a new type of "drop" ceiling that doesn't drop. It mounts right up to floor joists. Very easy to install and take down.

lee_7

i use a product from hd called pole wrap. It is a vertically segmented panel that wraps around pole and adheres with construction adhesive. Looks great painted or stained.

Steamhead (in transit)

But

we're not going to buy it from Home Depot. Does someone else sell this stuff?

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