Plumbing Zone - Professional Plumbers Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
63 Posts
Discussion Starter · #1 ·
just looking for oppinions really, doing in floor in my own home ( older home , solid joice not tgi engineered ) I have seen many different products for the pex installationg any recommendations from experiance. ? ones have seen before was simply staple up with foil back insulation underneath. or roxul insulation underneath. i know this way is easiest and cheapest but looking for some well worth it products, only doing it on main floor for now. basement slab later date.
thanks for anything helpful guys =)
 

·
Registered
Joined
·
398 Posts
Are you just doing one floor, in between joists?

The product I have used a few times is the Rehau heat transfer plates. They are made of thin gauge aluminum and you just staple them up with a staple gun and leave about a 4-6" seperation between plates throughout the length of the pipe. They work very well.

The company I work for normally uses Rehau O2 barrier pipe for our radiant, and it works great for in floor radiant that is encased in concrete or a concrete subfloor, but it's not so good for staple up. Reason is we had one job where we used it for a staple up retrofit and the O2 barrier for this pipe is a bit squeay due to expansion/contraction. I would suggest going to Wirsbo HePex or another type of Oxygen barrier pex for this application.

The heat transfer plates will help the pipes conduct heat better and spread the heat out better as well. As far as what to put underneath its up to you but Reflectix or Roxul will be fine. IF it's over an unheated garage, crawl space, or exposed area I strongly suggest you beef up the R value of the insulation below your radiant. I'd say R-12 if there is a heated space below and minimum R-20 if it's exposed below.
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #3 ·
that is what i was thinking to just do a much better job to use the transfer plates. was not sure what other maintstream choices there were.
how much are they for a plate? yea in between joices. old home but doing alot of reno's and figured why not do it. it does not cost that much for me to do
 

·
Registered
Joined
·
265 Posts
Radiant is an awesome choice for any home. The transfer plates are a great idea and that's all we use on staple up installations. The only thing to keep in mind is the thickness and r-value of your floor assembly. A good software program available from any of the major manufacturer's will get you the heat load and approximate water temperature. If you can find it, foil backed insulation with a 2" air space in between the tubing and the foil (faced towards the tubing) works great. Taco also makes a good mixing valve that monitors and automatically adjusts the temperature to the circuit.
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #5 ·
yea thinking planinng to use soundbar and roxul with 2 inch space for sound. and insulation to birds with one stone. lay out and what not is no problem. has any one here done such an install with solid joice layout? because i know on tgi there is allowances for penetrations up to certian sizes spaced out from each other . just dont want to run a line of one and a half inch hole through all the joices especially in line . maybe stagger them ?
 

·
Registered
Joined
·
398 Posts
I think that there are rules for repairing TGI's if you have to have holes spaced closer than their requirements. For example on one house I had to have holes spaced close together, there was no choice, so they called the engineer and anywhere that this was to occur that had to put plywood up overtop to reinforce it and then drill through that.

Haven't worked on many solid joists lately - they seem to be a thing of the past - what do you have? 2 x 10's or 2 x 12's or ?? Also - you shouldn't need such a big hole for 1/2" pex. I'd do 1" holes in your case and that will also facilitate the installation of an IC clip as well to protect the pipe from minor wood abrasion as it bends from one joist space into another. 1 1/4" or more is too big. If want to play it safe you could always just install a small drop at the end of your house and bring the pipes underneath the joists as they go from one joist space to the next and this will also allow the pipes to travel from one loop to the next, without drilling holes in the joists. A guy I worked with did this in his house and it worked great.

AS far as sound goes- what sound? It's radiant! You won't (or shouldn't if it's installed right) hear it.

I'm not too sure about the cost of the plates however. I believe the Rehau ones come in boxes of 100 if I recall correctly. They are about 2 feet long if I recall correctly. Factor that in plus a 4-6" gap between them, and figure out your total length of pipe and you can easily figure out how many you need.

What type of Boiler are you going to install?
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #7 ·
yea definatly goin to go with the panels. just need to find out pricing. and just goin to use roxul soundbarrier and soundbar so two things covered. the only thing is have solid 2x8 joice`s like not tgi with new homes. and from what i found there has been not much concern for where to put holes. just dont want a single run ( like a foot off load bearing) of inch and a half holes down entire home. maybe just stagger them. an just need to decide on heat source. ( just installed 2 stage condensing furnace) so for floor might use hwt... or tankless. hwt.
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #8 ·
dont think goin to go with boiler. i mean i would prefer to do a boiler. but after adding up the cost of trim etc. goin to add up to alot of money. havent decided yet. i know all the arguments agianst hwt use for it and tankless. but well money has a major bearing especially when you compare literally a 8:1 cost ratio for tank compared to boiler system
 

·
Registered
Joined
·
398 Posts
There are systems out there that use a Furnace's heat to heat radiant floors. It's like an A shaped type of fan coil that gets heated by furnace air. It really depends on how much radiant you have as well.

I can't for the life of me understand why you chose to get a new 2 stage furnace, knowing you would install radiant floors? I would sell the furnace and get yourself a small gas boiler, or an electric boiler if you can afford it. Small electric boilers can be quite inexpensive from what I have heard.

What type of HWT set up were you planning on going with? WEre you going to push domestic water through a heat exchanger? Or use some type of combi core system?

Personally though I would advise strongly against using any type of HWT to heat radiant.

Also - 2 x 8's are a little slim if you want to drill through them don't you think?
 

·
Registered
Joined
·
265 Posts
dont think goin to go with boiler. i mean i would prefer to do a boiler. but after adding up the cost of trim etc. goin to add up to alot of money. havent decided yet. i know all the arguments agianst hwt use for it and tankless. but well money has a major bearing especially when you compare literally a 8:1 cost ratio for tank compared to boiler system

I've used tank type water heaters on really small loads with a lot of success. I just make sure that I make it a closed system (auto feed, exp. tank, etc...) and it's dedicated to the heating system ONLY (no domestic). As long as you use tubing with an O2 barrier, you'll be fine:)
 

·
Plumbing and Gas SCO
Joined
·
1,437 Posts
On many new homes I have put 2 - 50 gallon Bradford White PDX HWT in to handle heating the basement slab and domestic. I use a LA-14 plate heat exchanger to seperate the domestic and glycol loops. Alot of people want the warm floor but don't want the expenses. I have the entire floor as one zone. The is no 24v on the system at all, even the t-stat is 110v.
Customers love it because it's so easy to maintain. I get to charge a higer mark-p on it than I could with a boiler system. Win-Win all around.
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #12 ·
furnace was only 1300 . straight swap. thats why. and boiler and trim. after all is done. about 7g. so pretty straight forward why. ive seen an done many hwt small radient systems. was just looking for better ideas. cost is a huge factor for most people including myself. thinking of putting a.o smith 50 gal tank. with seperate taps on the side inlet an outlet for heating loops .
 
1 - 12 of 12 Posts
Top