Old Church remodel

TheChurchman

Hello, recently I purchased an old church 1909 it has had multiple additions and originally had a coal fire boiler. it is almost 15k sqft. The previous owner put 2 small in floor heating units pexed to 8 radiators in the sanctuary, he also had an old wood burning boiler hooked up for external. I am interested in having multiple options for heating, cooling and circulation. the basement maintains a constant temp in the 50's year round causing massive condensation when windows are open in the summer. I was thinking of putting 3 house sized units in. The only experience I have with HVAC was removing the Asbestos from octopus units in the 90's. I have had multiple "professionals" in to quote the job and none of them agree on how to go about setting it up, (none of them wanted to bid it after seeing it either). I was going to try to set the system up myself since I can't find someone to hire. I know this is a long non in depth story but I wanted to start somewhere. I am located in Rush City, MN if people want to see google has great aerials of the property. Let me know and I will post the address. Thanks for any help!

Jamie Hall

It would be helpful to have a bit more information on what is really there... anything left of the original system? The one that had the coal fired boiler? Most likely not, but... and then what sort of radiators are fired by the in-floor heating units, and what are they like?

You mention that you want "multiple options" for heating? Anything particularly in mind?

Do you have enough land associated with the property to consider ground source heat pumps? If so, they would be a very good option (air source heat pumps are not. Rush City isn't all that far north, but it can get kind of chilly). They aren't cheap.

In any event, your very first project is to figure out how much heat you are really going to need -- and then start worrying about how to provide it. In other words, an accurate heat loss calculation for the structure.

Slant/Fin, among others, has a very good calculator here: https://www.slantfin.com/slantfin-heat-loss-calculator/ If you want to use it on your personal computer, scroll to the bottom of the page and there is access to a version for that.

TheChurchman

There is nothing left of the original system. I was going to put in an external wood burning boiler as the connections for that are intact and sound. I would like to run a natural gas boiler system. I was also looking at a forced air option that would heat but primarily for the A/C capabilities. My biggest issue right now is going to be getting the moisture out of the basement. The primary structure has a pitched roof and has a wood floor between the basement and main floor. The three additions are all spancrete floors and spancrete flat roofs making A/C units a good option, I think? I will run the calculator that you linked and let you know what it says.
The property address is 580 W 5th St Rush City, MN 55069

Jamie Hall

Moisture in the basement can be a real headache. First, find out whether or not you are actually getting water seeping (or flowing! It happens!) through the basement walls and floor. If you are, you basically have two choices: figure out how to live with it, or waterproof the foundation and provide adequate drainage so that groundwater is at least two feet below the slab (if there is one -- may well not be). In many situations, live with it may be the simplest option.

That doesn't mean you have to have condensation, though. What it does mean is that you have to have some means -- heat in winter, air exchange in summer and winter-- to keep the air in the basement well above the dewpoint.

I have to admit that I'm not particularly keen on exterior wood burning furnaces. They are labour intensive, not particularly efficient, hard to control, and -- in your area -- the fuel can be expensive (I don't recall Rush City as being in the middle of a forest area...). However, if you are young and vigorous, they do have some points.

TheChurchman

I have been working on the windows, the walls are old stacked stone and the window well bottoms were higher than the windows. So I literally had a waterfall coming around 2 of the windows in the basement, some grading, digging, and tar on the outside of the walls with class 5 and then covered with dirt and packed. The basement floor is concrete done sometime in the 90's they left a 6" wide trough around the outside edge that is about 6" deep and just soaks into the soil, if it gets too high it does run into an area that they did not concrete. I was initially worried about washout or freezing but the basement won't freeze maintaining about 50 degrees year round. I was thinking of putting in a gutter like system into the existing troughs and running them into a 55 gallon drum with a sump pump in it to cut down on future issues.

Jamie Hall

Indeed. You have one of those basements where "just figure out how to live with it" is much the best course. I've had a few of those... including Cedric's home.

One house which had a dry laid stone foundation and, in the spring, a real live (and rather lovely) waterfall down one of the walls...

Sigh.

The gutter concept works very well. It may take some experimenting to find a sump pump which is big enough and yet not too big.

The best thing to do is to make sure you maintain air circulation down there and maintain the temperature so that you don't get condensation. In the winter that's not hard -- it doesn't take much outside air to lower the dewpoint, and you can bring it in either by normal air leaks (!) if you don't get too fanatical aboit draught stopping or if you want to save energy you can use a heat recovery ventilator. Air exchange may not be sufficient in the summer, however, as the dewpoint of the outside air may actually be above the temperature of the basement walls and what have you. Depending on how bad the problem is, you might need to look at a dehumidifier.

kcopp

"the basement maintains a constant temp in the 50's year round causing massive condensation when windows are open in the summer"

Are you leaving the basement windows open during the summer?
If so that warm moist air will condense on the cold walls of the basement.... keep the windows sealed up and and a couple good dehumidifiers you will be ahead of the game...

mattmia2

I'm sure in a building like that the hot humid air from the main floor finds its way to the basement.

Robert_25

kcopp said:

"the basement maintains a constant temp in the 50's year round causing massive condensation when windows are open in the summer"

Are you leaving the basement windows open during the summer?
If so that warm moist air will condense on the cold walls of the basement.... keep the windows sealed up and and a couple good dehumidifiers you will be ahead of the game...

Agreed. I have an old basement as well. It was not much of an issue when I had a cast iron oil boiler maintaining temperature all summer, but once that was gone the basement stayed cool and damp. I sealed it up right and installed a dehumidifier. Now the basement stays about 65 degrees and is dry most of the time.

TheChurchman said:

There is nothing left of the original system. I was going to put in an external wood burning boiler as the connections for that are intact and sound. I would like to run a natural gas boiler system. I was also looking at a forced air option that would heat but primarily for the A/C capabilities. My biggest issue right now is going to be getting the moisture out of the basement. The primary structure has a pitched roof and has a wood floor between the basement and main floor. The three additions are all spancrete floors and spancrete flat roofs making A/C units a good option, I think? I will run the calculator that you linked and let you know what it says.
The property address is 580 W 5th St Rush City, MN 55069

The amount of wood required to heat that structure will shock you. Unless you plan on living there and will always be around to handle the wood, I would not go that route.