Radiant where the Garage door is

[Nivekdodge]

Everyone says the perimeter of the slab is important to insulate. Can you post some pictures of what you did at the door openings? I'm thinking a transom?

 

[yeldogt]

How will the transom affect the radiant?

Typically, I keep the tubing back a bit from the edge of the slab at the car doors -- this is an area that you can't get perfect insulation and you don't want to drive the heat out the slab edge. Just bump it back a bit. Along walls -- again ... you can go crazy and keep tubing form under cabinets ... but I find doing a standard layout does not over heat anything. I do keep tubing away from refrigerators.

You have to look at the space -- I make sure the hot water runs towards the perimeter. And placing them closer together on the permitter is what I normally do where there are lots of windows or doors. Some have the first loop at 12" -- I'm closer especially on an open wall.

 

[Nivekdodge]

but when you insulate the perimeter, what happens when you come to the garage door?

 

[finn]

My building was put up in two stages. Both have full perimeter insulation, but the older section suffers from a lot of heat loss / snow melt in front of the door, while the newer section does not.

In the process of locating the tubes with a thermal imaging camera, I noted that the tubes in the newer section are a good meter away from the perimeter walls, and, I presume, the door.

Actually a good idea for a shop, as it’s not necessarily a necessity to have uniformly heated floors, as you aren’t walking around barefoot like in a house.

 

[raspy]

finn,

Excellent post. Very good point. Heat is not needed right up to the edges of the slab. Hold it back. Put it where you'll actually be needing it the most, like in front of the workbench or where you'll be working on a vehicle, or under a desk, under an area that you store paint, in the bathroom. This minimizes the loss and maximizes the comfort. You can easily keep a shop warm without heating the entire floor area and you probably won't notice the cold floor unless you step there barefooted. Meanwhile the extra warm areas will really be nice where you spend your time.

 

[yeldogt]

but when you insulate the perimeter, what happens when you come to the garage door?

You hold it back or loop the return close .. you just don't want the hottest going right along the edge. The goal is to match the loss .. not dive the heat outside.

 

[yeldogt]

finn,

Excellent post. Very good point. Heat is not needed right up to the edges of the slab. Hold it back. Put it where you'll actually be needing it the most, like in front of the workbench or where you'll be working on a vehicle, or under a desk, under an area that you store paint, in the bathroom. This minimizes the loss and maximizes the comfort. You can easily keep a shop warm without heating the entire floor area and you probably won't notice the cold floor unless you step there barefooted. Meanwhile the extra warm areas will really be nice where you spend your time.

Again -- some this is use and location. In my colder climate you don't want to drop the effective SF down where you are now having to run higher temp water. I like to use the tubing as an effective comfort manager .. increasing where I want a bit more and still maintaining an overall floor temp. Even with a wall of base cabinets - I like to get a line of tubing under so that it's a barrier to any drafts. In really big spaces where lower temps may be desired .. zoning works. In my main studio when I'm working in the middle -- I can turn off the central area ... when I'm just thinking ,,,, I have it running.

You only get one shot at the tubing

 

[slowTA]

I think everyone is missing the point of the question (as I understand it).

When you insulate the perimeter of the building with Styrofoam, what do you do with the Styrofoam at the car doors? In my mind the insulation would be exposed and get driven over... or should you not insulate under the door openings?

 

[jlckmj]

My garage heats all the way out to the front of the framing, including the 6 inch or so area that is between the overhead door and the outside of the framed wall. (the first expansion joint of the driveway).

With a fresh snow I can clearly see where the heat stops and the cold starts from the snow melt, right at the expansion joint material.

Jim

 

[finn]

I think everyone is missing the point of the question (as I understand it).

When you insulate the perimeter of the building with Styrofoam, what do you do with the Styrofoam at the car doors? In my mind the insulation would be exposed and get driven over... or should you not insulate under the door openings?

Both of my buildings with insulated slabs have insulation across the door openings.

It gets torn up some and I have gravel drives in both buildings.

Aesthetically it’s not the best, but most of the foam is still there after about ten and fifteen years.

 

[finn]

Again -- some this is use and location. In my colder climate you don't want to drop the effective SF down where you are now having to run higher temp water. I like to use the tubing as an effective comfort manager .. increasing where I want a bit more and still maintaining an overall floor temp. Even with a wall of base cabinets - I like to get a line of tubing under so that it's a barrier to any drafts. In really big spaces where lower temps may be desired .. zoning works. In my main studio when I'm working in the middle -- I can turn off the central area ... when I'm just thinking ,,,, I have it running.

You only get one shot at the tubing

I’m most likely in a colder climate than you, but my building is a shop, not a studio, so I probably have lower set points than you, also.

The floor will maintain any room temperature set point I want, so far, even at sub zero temperatures, and I have 16’ ceilings. At most I am loosing one tubing pass when they left a 1 meter gap on the outside wall perimeter. Thats probably about fifty feet of effective tubing in that particular ~28’x32’ section of the building. I’m not heating the neighborhood.

Water temp out of the boiler is set to 109 degrees, and the boiler condenses well over two gallons a day in cold weather.

 

[Tduby]

I’m thinking of using this product in front of my doors I know it’s lower r value than styrofoam but still better than nothing
http://www.superiorprofiles.com/poly-foam.html

 

[raspy]

I’m most likely in a colder climate than you, but my building is a shop, not a studio, so I probably have lower set points than you, also.

The floor will maintain any room temperature set point I want, so far, even at sub zero temperatures, and I have 16’ ceilings. At most I am loosing one tubing pass when they left a 1 meter gap on the outside wall perimeter. Thats probably about fifty feet of effective tubing in that particular ~28’x32’ section of the building. I’m not heating the neighborhood.

Water temp out of the boiler is set to 109 degrees, and the boiler condenses well over two gallons a day in cold weather.

Exactly right. In a shop especially, you don't need to heat clear to the perimeter and it doesn't mean the water will have to run noticeably hotter to keep up. But it does mean much less loss to the outside. A good rule of thumb is that you only need to heat where you might actually step. In a house, this may be done differently, but there are still areas that don't need heat, such as the perimeter within 1' of the walls, in the pantry, under the refrigerator and under the fireplace. Sometimes I'll leave heat out of one area so I can run the floor warmer in another part of the same room. This might happen in the laundry where I want a nice warm floor to step on, but need less under the machines. Or way in the back under cabinets, where no hea is needed, but a lot is needed in the kickspace area. Or in a walk in closet. Closets need the leasst heat of any room, but it's nice to have a warm floor where you might be bearfooted. So leave it out where the clothes are hanging and heat the area where you walk. None of these omissions mean the house is hard to heat, they mean it's more comfortable to live in.

I have (5) 120 gallon solar storage tanks, a water heater and a solar drain back tank as well as a line of big tool boxes in the garage/shop. No heat under any of that. And I held it back from the two 10 X 10 doors too. But in spite of that, the whole room is very comfortable as measured by air temperature and the floor is warm where I sit, where the workbenches are and where I work on projects or the truck.

There is no set temp being delivered to the floor because it is almost always heated by solar. In the shop, I don't mind if it's a bit cool sometimes and the thermostat will turn it off when it reaches full temp. Having an 8" slab means it can carry over for a day, if needed, without heat. This type of control and heat source is not well suited to constant circulation. It circulates when the primary thermostat is calling and there is solar available. A second thermostat controls the oil backup. The oil can only run if I have it set to allow it, and the solar is depleted, and there is a call for heat on the primary stat as well.

 

[yeldogt]

I always set the garage floor 2" above the apron -- so the insulation under the garage slab hits the apron. I like doing a thick apron .. so 2" of the garage slab is in contact w/ the apron. There is no good way to avoid this ... I often do cedar boards in driveways for layout ... but I don't like anything at the apron/slab joint

This way the garage door comes down on the apron and protect the 2" edge of the slab -- I'm in the mid-atlantic ... so we have wind and leaves .. I don't want stuff blowing onto the garage. The raised slab stops stuff rom blowing in and the door protects the open edge from the outside.

You can go crazy with trying to minimize loss ... but, I try for low water temps .. and you must have enough tubing to make this work in colder climates.

Raspy obviously knows his stuff .... my only concern is he is in a higher solar gain area. In the north east USA with cold damp cloudy winters the solar gain is not going to give you any breaks.

With an open wall of windows you may want to have the hottest tubing in a loop along that wall ... if cabinets on a given wall I will use it for the return loops (colder)

In my area in concrete -- 6" spacing is foolproof and provides an incredible balance. I don't like 12" spacing ..

 

[raspy]

yeldogt,

Sounds like you guys have it rough in the winter. Fortuantely, here at about latitude 38 and in the high desert, the sun is strong almost all the time except for an occasional dreary few days in December or January. The altitude of 5,000 ft makes a huge difference over sea level performance too.

6" spacing is a very good way to deliver a lot of heat and not notice variations as you walk. The main problems, as you know, are the work to install more tube, more loops at the manifold and the extra vulnerability when pouring the slab, as the finishers cannot step anywhere without being on the tube. Pour days are nerve wracking.

 

[yeldogt]

yeldogt,

Sounds like you guys have it rough in the winter. Fortuantely, here at about latitude 38 and in the high desert, the sun is strong almost all the time except for an occasional dreary few days in December or January. The altitude of 5,000 ft makes a huge difference over sea level performance too.

6" spacing is a very good way to deliver a lot of heat and not notice variations as you walk. The main problems, as you know, are the work to install more tube, more loops at the manifold and the extra vulnerability when pouring the slab, as the finishers cannot step anywhere without being on the tube. Pour days are nerve wracking.

There is no "one" answer. Most people who are asking on this forum are doing it for the first time .. or maybe going to copy someone else. IE: My neighbor's place has no slab insulation, 12' tube spacing, R13 walls with no ceiling insulation and his place is great .. toasty all winter. Easy to achieve with a big enough boiler and hot enough water in the tubes .. but not very efficient use of fuel.

The best place to see this effect is in large commercial spaces where they heat pockets of a large building to various comfort levels.

But, you understand all of this .. and do more of these vs me.

25+ years ago when I was doing my first projects, little information was available -- to be on the safe side ........looking back, we went overboard with the the loop length match, number of loops and manifold complexity. You learn along the way, like anything, there are things that can be eliminated or designed in to make things work w/o adding cost or complexity.

The 6" tube spacing works great in my area -- it gives a bit more response speed and since most of my projects also have wood floors .. it's keeps the temps very close ..often the same. That keeps costs down if I can keep one temp. Tubing is not a huge cost -- and I loop together so if something idd happen to a loop it would still work

The OP's question is a classic example -- no one ever thought of it until they noticed the snow never stayed along the door. Then you understand .. hay, I have some heat loss. I actually want some heat loss there -- to keep it all clear ... but not to the point where I'm heating the whole apron. The only way to really tell how much loss .... is to look at the return temp on the loop.

 

[jacks2000]

We put a 1" piece of foam board vertically against the side of the slab about 3/4" down from the top. We cut a small 3/4" scrap of the foam board and layed it on top and held it in place with some ling nails. After we poured the apron we pulled up the scrap and poured some caulking in the slot to protect the foam board and keep the dirt/water out. Made a nice clean transition. We haven't had enough snow to see if there is much heat loss there.

 

[like2wheel]

We put a 1" piece of foam board vertically against the side of the slab about 3/4" down from the top. We cut a small 3/4" scrap of the foam board and layed it on top and held it in place with some ling nails. After we poured the apron we pulled up the scrap and poured some caulking in the slot to protect the foam board and keep the dirt/water out. Made a nice clean transition. We haven't had enough snow to see if there is much heat loss there.

Hey, that sounds like a good solution.
Where is that joint relative to the garage door?
Any pics?

 

[yeldogt]

Hey, that sounds like a good solution.
Where is that joint relative to the garage door?
Any pics?

You can use a piece of Cedar -- or a typical tar strip .. the caulk will eventually fail .. that's why we do how I described above.

 

[mygarageone]

I used the old style expansion joint material at the apron , door threshold . That makes a Hugh differance I see very little bare concrete in the winter . I ran my tubing with in a foot of both garage doors openings.

 

[Nivekdodge]

I think everyone is missing the point of the question (as I understand it).

When you insulate the perimeter of the building with Styrofoam, what do you do with the Styrofoam at the car doors? In my mind the insulation would be exposed and get driven over... or should you not insulate under the door openings?

Bingo

 

[yeldogt]

Your Post says "radiant where the garage door is" It's only in the body where you mention the insulation. And transom ?? you never did say what you referred to with "transom"

People gave you lots of ways to handle both ..

 

[73surffisher]

I like Jack2000's idea for the transition at the garage door. As I'm getting ready to do this myself, I would like to ask the OP and others, , for the perimeter walls, did you cut the polystyrene at the top at a 45* angle or leave it 90* and have the concrete poured flush with the top of the polystyrene?
Or am I square rooting the to much ?

 

[PDM]

assuming you have your driveway or access paved or concrete up to the garage ?

I had long medium gauge stainless strips cut at Metal Supermarket and epoxy glued them down over the insulation strip - extending about an inch on either side of the garage and my concrete driveway. Acts as a nice transition over the foam insulation, and allows my overhead door seals to sit right on the stainless.

 

[finn]

45 degrees. Or maybe 60 degrees.

 

[73surffisher]

Thank you Finn