Radiant Floor Rebuild

kiwegan

Hi, I am new to the forum and am looking for ideas about our Radiant Floor System.

We recently bought a house (we live in MN) and discovered the Radiant Floor pipes in our basement floor are cracked in multiple places in each of the 6 loops due to the house not being winterized while being sold. We have been told that the present system is unusable. The size of the basement is roughly 1500 sqft. We don't have forced air ducting down there and the present forced air furnace is not sized to include the basement. We would like to look at our options and the pros and cons of each, regarding heating the basement.

The options we know about so far are:
1. Replace the present radiant heating system by ripping out the floor and relaying the concrete and pex piping.
- Con: expensive
- Pro: Efficient heating

2. Use gypcrete to lay on top.
- Con: puts our stairs and walk out door out of code
- Con: fairly expensive
- Con: We have a 8ft ceiling height. This would reduce it further.
- Con: Seems there is plenty of discussion of how good it is.
- Pro: Don't have to worry about ripping our existing concrete.

3. Baseboard Radiant Heating
- Con: Not as effective as in the floor radiant floor.
- Pro: Cheaper than in floor radiant option

These are what we have right now as options. Does anyone else have any thoughts?

Thanks in advance.

Anthony

DangerMouse

Hi and welcome to the forum.

I guess it depends on how much effort/time/$$$ you can put into it.
Option 3 would work just fine and I don't think it's any less efficient as a heating source, is it?
Lots of work and *unknown problems* with the other options.

DM

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beenthere

And how do you know your current hot air furnace isn't sized to be able to heat the basement.

Subground basements don't take much to heat them.

Does your current hot air furnace run 24/7 on the coldest nights. If not, you can heat the basement with it. i would zone it.

Won't be as comfortable as the radiant though.

kiwegan

We have a 4 ton unit and we put a ECM motor in it's place to make it more efficientand effective. We have approx. 3500 sq ft on the top two floors that sit on top of the basement. This heating unit, along with it's ducting is sized for these two floors and no more. THere is not enough room in the basement ceiling either to place anymore ducting to add for the basement.

Yes, our furnace is running a lot to keep up with heating the two floors it does now. Each floor is also zoned. I am thinking that it would cost more than just replacing the floor, to add a system for forced air for the basement.

Unfortunately I feel the forced air option is too challenging to implement.

Thanks for all your feedback and thoughts.

Anthony

kiwegan

Yes, it is not a good situation, either way I look at it. Because the piping is not surrounded in concrete, I am sure the efficiency has to be less in the baseboard option.

Thanks for your response.

beenthere

Duct work for a basement is relatively small.
Cost could be more, or a lot less then for ripping up your floor and running a new radiant loop.

1500 sq ft underground basement is around 15 to 20,000 BTU's to heat.
The forced hot air system is running more now because the basement isn't heated right now.

Once the basement is heated again, it won't run as much to heat the first floor.

Many companies will look at it as being able to make more money off of a radiant or baseboard system, then zoning. And will tell you the forced air system isn't big enough for the basement.

But. radiant will make the basement more comfortable then any other type of heat.

How often are you going to be using the basement. With radiant, temp setback doesn't work well. Specially in a slab. takes to long to heat up the slab.

kiwegan

Hi Beenthere,

That is so funny (ironic really) that you bring up the subject of why my system is always running as I never mentioned that, yet you answered a separate question I have been having with my Geothermal installer about why is it running so much (we have just had Geothermal installed which is how we discovered our radiant floor was broken). He also said the same thing; that because the basement is not heated that is was causing heat loss and hence it is why the unit is running so much. I am struggling to believe him, but after you mentioning it and the fact that it is 62 degrees in the basement without us even heating it, lends me to think that a lot of heat is getting into the basement. So thank you for that comment. It helps me to feel better about why the compressor is running so much.

Anyway to answer the original question you had, you make a good point about setback and I do have to think about the usage factor. All good thoughts. My thought initially is that we will use it a fair bit since I plan to build a home theatre with wet bar and an exercise room. I love movies, so I am thinking I would be down there a lot ..... I hope. The other thing is that with Geothermal, those systems don't typically lend well to temp adjustment anyway, so I would pick a temp and leave it at that for the basement.

The one other thing I forgot to mention is that we already have our Water to Water unit installed for our geothermal to heat the radiant floor. I am guessing it would be kind of hard to have to swapped out, or even removed to go to a forced air unit. The forced air geothermal was sized for the two floors above only and if I was to include the basement in that calculation then that unit would also need to be changed to be able to handle the extra load.

That is the only reason I was trying to think of a way to still use Radiant Heating of some kind ....

Anthony

forresth

I think I'd lean towards baseboard heaters or old fasion radiators in your shoes.
I bet you could find them real cheap used.

I haven't looked to much into those systems yet, but I'm real surprized that there wasn't some sort of anitfreeze in the system.

beenthere

Is the water to water geo you had installed set up to cool the basement also.
A home theater generates a lot of heat. So will the people. So you will need A/C in the basement now.

So how are you planning on cooling the basement in the summer?

jogr

You already invested a boatload of money on a state of the art geo w to w unit to heat that basement and it's just sitting there like a paperwait right now because the installer assumed your in-slab tubes were ok - right?

If that's the case you don't want to waste that big investment. Baseboards are out - the geo temp is too low for that. A good HVAC company might be able to put in an air handler with hydronic coil to heat using your geo w to w. The only way to find out is to have one look at the details of your situation.

Another option to use your geo w to w is to put radiant tubes in the walls. Again you'll need a pro to design it but he might let you do the tubing install yourself to save some cash.

You may as well at least get a quote for having the floor redone though because warm floors would be very comfy.

Lastly, I wonder if the owner who let it freeze before closing, the home inspector or your insurance company should be on the hook for this. But that's not a discussion for this forum I guess.

Home Air Direct

I have been involved in several "after-pour" projects, and it really is not that big of deal. If you can spare loosing a couple of inches of ceiling height, it is do-able. One of the harder obstacles to overcome with the after-pour is making sure the sub-structure is sound and can hold the added weight. In your case, this is not an issue, and you are already set for level.

Insulate with WBBF (White, bubble, bubble, foil) lay the wire/rebar, run the loops, attach to wire, connect to controls. Running Barrier Pex is really not rocket surgery. Just have a good design in advance that matches your heat loss. If you are not comfortable with the controls portion, hire a good HVAC Pro that is knowledgeable in hydronic heat controls. Do not assume that all HVAC pros know hydronics. They don't.

Good luck with your project. As stated above, it is a shame to have the level of equipment that you have and not be able to have the system that was intended.

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kiwegan

Everyone responding here seems to be very insightful and are reading between the lines very well. I am very impressed. Forresth, you bring up a very good point, especially living in Minnesota .... . My Geo. installer, who also specializes in Radiant Heating also said the same thing. Fortunately the house is not that old and I found out who the original installer is and asked him the same thing. He said that he has installed hundreds of systems and that he has never put anti-freeze in the systems except if it is installed in a garage. I asked if the homeowner is away on holiday and the heating system fails for some reason. He said that you should never not allow your heating system to fail. At this point I clearly knew he did not know what he was doing. He also said that I only had a one year warranty and that he was not going to be doing anything about the system he installed, since it was 3 years old. I was left high and dry. So now I am faced with this decision I am trying to make now.

Thanks for your thoughts on what I should do. One question; are baseboard heaters as efficient as in floor heating?

kiwegan

Hi Beenthere,

Yes, this unit will be doing the cooling also. The warm water will be exchange with the cooler water in the geo lines and dump that heat into my hot water system or the earth. Good question though. I am hoping to confine the home theatre equipment into a little side room that I will be insulating for acoustics and heat management.

Anthony

kiwegan

Hi Jogr,

Thanks for your ideas. I am glad you mentioned about the baseboard heat as I did not know that, but that does make sense. It makes the decision a little easier, since that would take it out of the equation.

Your first paragraph is on the money. Yes, until we fix this, the unit is sitting there only to heat our hot water at present. It is not hooked up to the radiant floor right now.

I am hesitant to look at air options right now since I don't really have the space in the ceiling to run the ducting and I am not sure that the present system is sized to handle the extra square footage. I think even if I do consider it, the cost would be close to Radiant Floor replacement and if that is the case, then I would definitely prefer the Radiant Floor over the Forced Air.

Now I must admit, I did not realise you could do in wall heating. That sounds like an interesting option. I will definitely like to look into that a bit more.

We have had a rough estimate that it would be between 10K and 12K to get it replaced, which I admittedly is not as bad as I thought it would be, not that I could not use that money for something else.

Unfortunately, this was a bank owned property, so in our research for coverage and ways to get it covered, the bank obviously will not claim responsibility for it, even though it was them who did not winterise the house fast enough and ultimately it was the installer who did not put anti-freeze in it. We tried to have it tested when we bought the house but the inspector said he could not test it. It was then our fault for believing that since the plumbing was okay, that then the radiant floor should be okay. A bad assumption on our part. A hard lesson to learn.

We have not approached our insurance company as we thought that they would not cover this. Is this something you think we should try to do?

Anthony

kiwegan

Thanks Home Air Direct. This is good to know, as it was suggested to us as an option. The one question I have for you then is the Code factor. How do you deal with the code restrictions on stair cases and walk out doors? since this would change the height of the first riser in the staircase and probably put the concrete at the same level or over the door threshold.

Anthony