Insulation Question For Wood Floor Staple Up

K Penniman

This summer, my contractor finished installing a Trinity boiler and staple up Onyx tubing 8" OC. It has been a seasonally warm fall, yet my propane consumption has increased to an average of 3.8 gallons per day in October and November. Comparatively, before the heat turned on I was using 0.7 gallons of propane per day for my range, hotwater (separate heater), and dryer.

My heating area is small, about 900 square feet on the main floor. However, I have no dedicated heating for my second floor where the bedrooms are, so heat rises up there. I live in a 14-year old log home and the logs supposedly have an R-value of roughly 12-14. I have lots of Andersen windows that really warm the place on sunny days but lose heat at night. My thermostat is set at 68.

My floors are a mix of tile and birch - the wider planks are curling a little, which they tended to do before I installed the radiant and relied on my wood stove. The radiant tubing is stapled to the subfloor and I've used 1" reflective rigid fiberboard to insulate the tubes, leaving a 2" air gap. Some of the foam boards are loose and probably leak air and I have yet to seal the registers cut into the floor that accomodated the forced hot air I replaced.

My question is this: Would I experience a noticeable improvement in efficiency and propane usage if I installed R19 fiberglass batts up in the joists (paper side down)?

I'm in the process of finishing my basement, so access to the joist bays will soon be more difficult (they'll be sheetrocked). I'm willing to invest what it takes to get the radiant working as best as possible - I love my warm floors!

Any suggestions are appreciated.

Kip in Vermont

hr

Yeah I would

add the additional R-19. For that area you are not talking a lot of bucks.

Was a heatloss calc performed to assure the system can meet the heat load?

Logs and lots of windows throw up warning signs for me. It's infiltration and low R value that need to be considered with logs and glass.

If additional heat is needed, best to do it before the finish below.

hot rod

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Uni R

Chinking

What's the condition of your chinking? It's extremely tough to get a log wall's surface very tight. Also, I'd be skeptical about any R values given for log walls.

K Penniman

Thanks for the responses.

I believe a heat-loss calc was done and the Trinity 150 was deemed more than adequate. Think I should use foil tape to seal the edges of the celotex foam board before putting up the R19? Is that overkill?

My log home is based on a tongue and groove system, so there is not any chinking. It feels pretty tight. I've found that the edges of certain windows tend to be a little drafty. I may take off the trim work and add more expanding foam.

I must be losing heat to the basement, it's warmer than it should be down there. I'm hoping the R19 will cure that. I'll happily hear any alternative ideas.

Kip

K Penniman

Here's a link to the log construction:


http://www.northeasternlog.com/fourstar/advanced.php

hr

Go with the R19

hard to overkill insulation.

Sounds like the boiler was sized to the building load, however I am more concerned with the ability of the tube to get the heat to the space. Make sure you have a Watts Radiant "Radiant Works'calculation to prove the installation application can meet the load with the 900, or less, square feet of floor space available.

900 square feet at lets say 20 btu's per square feet, from the floor only gives you a 18,000 BTU/hr system, regardless of the boiler size.

I imagine cabinets and other built-ins would cut down on the actual emmitter square footage. Best to be sure before the real cold sets in.

If at all possible find a contractor to do a blower door test on your home. This will give you a real life picture of any infiltration losses. Fun to watch, also. Some utilities will provide this service.

hot rod

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Uni R

Wall R-Values

The R-value for wood ranges between 1.41 per inch for most softwoods to 0.71 for most hardwoods. Judging by illustration with the 12" spike holding the logs together vertically, those logs look to be just under 6" wide near the T&G sections. They do make a lovely end home. I remember an aunt had a cabin builty in the rockies and the builder channeled the bottom of every log to stuff it with wiring and insulation. Big logs and a huge job. What is your roof insulation like? You definitely need to stop the downwards heat migration to the basement, unless you want to insulate it and use it as living space.

K Penniman

It was around 10 degrees last night and the house was at 68 where I had set it. I notice that often the temp rises about 2 degrees over my setting. Hopefully, if I can prevent heat escaping into the basement I will see a reduction in my energy usage.

Regarding the floor space. The exact floor measurement is 864 square feet. Then I have to take into account the stair well, the tub, and the kitchen and bathroom cabinets. I have a thick area rug in the living room and a fibrous sisal area rug in the dining room, both on the wood floors. I'm sure this cuts down the ability to heat these room, however, I would like to keep the rugs as they are.

I've also noticed that once the boiler turns on, it works for a considerable time before shutting off. Maybe 30-45 minutes. Then it may be quiet for an hour or two or more. I'll have to take better notice...

K Penniman

In fact, I'm in the process of making my basement a living area now. The framing is complete and I intend to make it very well insulated. I'm using the Trinity to provide baseboard heat to the new space on a separate zone from the upstairs. It will add about 650 square feet of finished living space.

Uni R

Run times

The trinity modulates its heat down to about about 50K, but not low enough for it to run all of the time for your needs. Ideally it would run the whole heating systme if it were small enough and could modulate enough.

Uni R

Basement

R19 twixt the joists may ruin your radiant ceiling! You may want to first inulate the envelope and then decide just how much insualtion you want and need in the joists. You could even bump up the insulation a bit in spots like under the rugs upstairs to even out the heat/

K Penniman

Basement

What does "insulate the envelope" mean?

And do you think I should also add the foil tape? I'm hoping it won't make a difference because it would take me some time.

I've included some pictures of the heating area. You can see the quantity of windows, the rug, and in the hall photo, a large register in the floor. I'm not sure how to seal those regesters.

Uni R

Envelope

Very nice place Kip. Excellent scenery...


The envelope is just the outside perimeter of your house. Anywhere that heat can flow to make it's way outside of your house. Once you have finished insulating the outside perimeter of the house (and all I think you have said is left is the basement) then you'll have an idea of just how much heat you want to stop from going downwards and then adjust the joist insulation correspondingly.


BTW, insulating basements is probably the most controversial area to insulate. For your locale you may want to use a thin layer of closed cell styrofoam glued together on the outside and then a framed wall inside of that using pressure treated lumber for your base plates. With this set-up don't put up a vapor barrier behind the drywall or whatever you use for the inside wall. Additionally, I'd use a rock wool insulation product like Roxul rather than fibreglass because it can still provide decent R values if it gets wet, it is more immune from mold and is less irritating to work with.

hr

Looks comfy

I'd still want to know that the radiant floor was calced with those area rugs and other non nheatable floor spaces.

How do you supply combustion air fro the wood stove? or is it decorative? That air vent, or the flue from the wood stove will cost some heat, unless it can be shut off.

Chimneys are like big "heat removing" straws.

I don't mean to question the installation, but I have underheated a few log homes in my days it usually shows up a few years down the road when logs shrink and infiltration skyrockets. But I have also missed some by not questioning the finished floor coverings.

Many times homeowners claim only hardwood and tile but this can be a noisy home and area rugs are added to soften accoustically or for design look.

Nothing wrong with that as long as the radiant floors know the plans and what can be expected from them.


A little extra care now could prevent you from a home that does not stay warm at or below design temperatures. All heating systems work fine on mild days Hate to see you have to burn the furniture in that stove to stay warm in those Vermont winters.

hot rod

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Brian

Trinity

Kip
What is the temp of the water going to the floor?Is the outdoor reset hooked up on the Trinity.Which model of Sentry controller do you have (look on top of the controller it will be 1.# 2,3or5.Also transfer plates on the radiant will allow you to lower your temp. but still get the same heat to your main floor.

Good Luck
Brian

Unknown

can you even use transfer plates with onyx? hmm.

Put in the floor insulation. You don't want a radiant ceiling in the basement at the expense of upward performance, ESPECIALLY not in your case.

I would suggest spray foaming the cracks in the foam board, then adding your additional insulation. fiberglass sucks at stopping infiltration, and infiltration will kill your particular type of system's performance.

Though I have to say I am *EXTREMELY SKEPTICAL* that a suspended tube application will cut the mustard in a vermont log home. I run heat loads on those homes all the time, and I have yet to find ONE that I would be comfortable relying on suspended tube to heat. Not one.

If onyx will accept plates, take down your rigid foam, buy some plates, and get them in there.

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K Penniman

Onyx

thanks for all the responses.

i'll check which model sentry i have tonight. the outdoor reset is on. i didn't think onyx (onix?) tubing accepted plates - could anyone confirm this? i'll check the water temp going into the pipes tonight, i think it's around 145.

my contractor, a vermonter, insisted that my system would be ample to heat the house comfortably. so far so good. i still use the wood stove, mostly because i really like sitting in front of the fire and i have lots of wood to burn.

i'll go to the hardware store today. what type of foam spray should i look for?

thanks again for all the assistance!

kip

K Penniman

Sentry Version T1.2

I checked out the Sentry on my Trinity 150 last night. It's version T1.2. The water temp going into the pipes was as high as 155 degrees.

I started sealing the obvious air gaps with foam sealant and stapled up R19 batts. The basement should be cold as there is not dedicated heat down there at the moment. However, it's quite warm, to my dismay. Hopefully my efforts will pay off and keep the heat out of the basement.

Just how diligent do I need to be when spraying foam? Most of my celotex foam boards are cut to fit tightly in each joist bay. However, some of the boards move pretty freely if jostled. Should these be sprayed around all the edges, or is stapling up R19 sufficient?

Thanks for all your help.

Kip

Unknown

Insulation is one of those things where your attention to detail can pay off. The tighter you make it, the better it works. Take a little time and do it the best you can, you'll only get one shot and you want it to work as well as it can!

Pay special attention to the rim joists; those were sealed tight, tight, tight, right? If you doubt this, pull down your rigid there and look, and do whatever you have to do to get good R value in the rims, and spray foam the heck out of them to seal it up.

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