I still think you’re okay with your slab installation, around here what you did is standard practice and seems to perform well. It’s important to remember that you are no insulating against really cold temps. What are ground temps, 53 degrees? Just my 2 cents worth.
I hope your right Bartman. So most guys are doing it that way then? also, how can you run water at 170, meaning so hot through your floor? does this then make the floor cycle more on and off, rather than a lower temp and a steady pump? Your right, 52 degress, but won’t there always be cold to attract the heat, maybe a 20-30% draw?
My cousin has grade slab, and pretty much no perimeter-edge insulation. It reaaaaaally draws power. Not sure how it can really be fixed. Dug out maybe.
Anyone have suggestions?
The slab gets warm, and not too warm, my basement bathroom ceramic tiles are warm, not hot, the rest of the basement is carpeted, I don’t think I would like the temp any lower. Remember, plastic doesn’t transfer heat like CU, AL or steel, and when you are heating such a large mass like the slab, it’ going to take a while to warm and cool. My heat cycles in my basement maybe once a day it’s hard to say, I’ve never relly monitored it. My future plans are to install a PLC to run the boilers/zones/monitor stack temps, maybe I should look into logging data, like monitoring zone run times. As far as your friend is concerned, I would dig out around the foundation’s perimeter and drop in 2” insulation down along the wall, you could “stucco” all the exposed insulation above grade to look like concrete or stone.
I love my radiant heat, the efficiency seems good, but it’s hard to say about the garage since I have a big heat loss, a 16’ overhead door. The concrete was supposed to be 4” thick in both areas. This summer I installed a bathroom in my basement and had to cut the concrete for the drainage and ejector pump sump, I had a hell of a time cutting it out. When I set up for the pour a day earlier I sprained my ankle so I couldn’t be everywhere and had to trust the idiot I hired to do the slabs, more on that later. Below the reinforcing wire and heat tubing I laid 4 mil plastic as a vapor barrier for under the concrete. The plastic produced a problem with the concrete setting up because we poured in March and the concrete had to have calcim chloride added to help it harden, I was not happy about that. Needless to say, we had to poke holes in the plastic to get the water to drain from the mix. As I was chopping out my concrete 21 yrs later, I found 4” above the plastic and 2” below the plastic with the tubing 2” below the surface, (at least that went as planned). Undoubtedly the 6” total thickness is not consistant through my basement slab, but it’s pretty thick considering that most basement slabs are about 2” thick, around here anyway. My garage is 19x20 and has a trench dug across the middle in each direction in the shape of a cross dividing the slab in 4. Although the slab is poured as one, the “haunch” that runs across in both directions adds another 8” depth about 18” wide for reinforcement.
i always thought that you could run hotter water into the slab. i was told only 120 to 150 or the concrete would break up from the heat. i still installed a mixing valve to be safe. at 120 my brother in laws basement works like a dream and since insulating basement walls maybe kicks on once a day for 3 to 4 minutes at really cold outside temps. i learned allot from installing his radiant and did do some things different. i posted before but will post again radiantdesigninstitute.com is a great info site to use for all sorts of projects. i did my new house radiant using most of the ideas on setons website and makes allot of sense to me. most of radiant are just ideas and who knows what is the best way to do it.
I agree Rider, I was told that too, but if a guy has been doing it that long has to be OK. I have cracks in my floor, dont know if they would have happened anyway, but I ran pretty hot for a while before I got a mixing valve.
So yours (brothers)kicks on once a day you think? Sounds good. Any way you know or could find out what kind of return temp you get out of the floor? It would be great to know the return (water temp coming out of the floor) when the pump first kkicks on, and again the temp when the slab is charged. Id like to compare it with my cousins- he is always cold return.
Anyone know a good place to find a contact temp gauge reasonable?
barnartist ill check it out tonight and let you know the temps. i see your sign on 70 all the time nice. checked out your site looks good. i live key ridge off of st rt 147 toward bellaire oh.
Ryan, went to the link you provided and it looks like my floor is crap. Im pretty much losing a ton in the ground. My fault really. I will need to either poor another floor one day or find an alternate way to heat it. Maybe baseboards.
i dont think it is crap just works different in that you heat the ground and when the power goes out you have stored some heat in the ground for the floor. i would try to insulated around the outside of the foundation or slab if you could and insulate the walls if its a basement or garage if not already done. it should still work your just dumping heat in ground for later use. that is the thought that ive read on the net.
In the past I have done a few radiant jobs, each one a little different. In a wood floor I would never go above 120F, concrete takes a lot longer, I can’t see how a radiant basement zone could run for a couple of minutes unless it’s on a timer. To warm a slab that zone has to run for a long time, and then after that you have to satisfy the thermostat. My floor has no more cracks in it than normal, I can’t see under the carpeting but the shop area is fine, no cracks. When I ran the basement loops I did 2, 1 loop on the north side of the columns, 1 loop on the south side. The loops are 1/2” polybutylene spaced 18” apart. The garage has 1 loop, starts out across the garage door (south wall), then travels along the exterior (east wall), then returns toward the south wall and goes across the door again, then returns back to the same path. Along the outer walls the tubing spacing is 6”, this spacing is accomplished 3 times, then the spacing goes to 12”, then 18”, then 24” is the final spacing at the inside corner of the garage. The garage has a few cracks in the concrete but I attribute that to that same idiot that did my slabs. The garage and basement were to have 4000lb mix, and I was told yhat’s what I received, until I spoke to the ready mix driver. The driver told me he delivered 2000lb mix for the garage, and 3000lb for the basement. When I installed the system I worried about cracking, but the garage cracking started before I ever had the heat operational.
i didnt have time today to get the temps going into the slab and out of the slab and i may have to use a strap thermometer to do it since he only has gages way before the radiant zones. his gages are located were the water is coming into and out of the house. i do know the thermostat shuts off way before the water coming out of the slab is hot. im only talking about the thermostat being satisfied when i talk about the slab working good. you are right that it would take a long time to get the temp coming out of the slab the same temp going into it. and it does take some time to get the slab up to temp like hours but this is mainly at startup. of course maybe i over shot my estamate it might be more like 15min to satisfy the floor zone ill check on that. now i do know his garages do run more often and for allot longer since they are not insulated much on the block walls and the 18’ door.
im known to be wrong about numbers some times ha ha
(hope that web site helps)
ryan
