KubotainNH
Veteran Member
Nice post, I forgot about the moisture barrier and pressure testing the pipes.
radiant heat checking on a few facts
- Thread starter mlinnane
- Start date
- Views: 4620
djradz
Veteran Member
I notice several posts discuss attaching tubing to the foam board, but make no mention of installing metal screen, mesh, or rebar. Around here, the typical installation is to use foam board, but then install metal mesh on top of. The tubing is then tied to the mesh. I personally would not install concrete without it unless I was going with fiber-crete.
woodlot
Gold Member
We poured fiber reinforced cement which eliminated the need for wire mesh. I know this is a debateable topic. I guess time will tell how good of a decision it was. The good thing is that I have 100% confidence in my concrete guys. They have been doing this for a long time and are known as the best around. I had to schedule my pour a few months in advance just to get these guys.
inveresk
Platinum Member
Djradz, I always use mesh. No exceptions. The mesh has to be located within the concrete topping for it to have any structual benefit. If it sits direct on the insulation, it's only purpose can be as a grid to which to tie the pipe. These are the reasons I place the mesh over the pipe and not under.
woodlot
Gold Member
<font color="purple"> "The thing that would make me nervous about installing in a barn is that if for some reason the furnace kicks off and you do not know, you could end up with a bunch of bad piping although pex does expand some. You could always use an antifreeze but then would need a heat exchanger."
</font>
I will be using PE (glycol) about 40-50%. Note that this is heating grade PE and not "RV" antifreeze. There is a diffrence, also, most people do not realize that "RV" antifreeze is already diluted.
Your stament about the use of a heat exchanger does not come into play for me. I have a "closed system." I'm assuming by your comment that you have what is referred to as an "open system." That one where your potable water is also used for heating. Some people use such a system and feel its fine and safe, others refer to these sytems as "killer" systems due to the risk of legionnaires' disease. A system like that really is a good incubator for legionella bacteria. I ruled out such a system early in the planning stages. I know one big internet DIY site promotes the use of open systems. All of the "pro" sites immensely denounce them.
</font>
I will be using PE (glycol) about 40-50%. Note that this is heating grade PE and not "RV" antifreeze. There is a diffrence, also, most people do not realize that "RV" antifreeze is already diluted.
Your stament about the use of a heat exchanger does not come into play for me. I have a "closed system." I'm assuming by your comment that you have what is referred to as an "open system." That one where your potable water is also used for heating. Some people use such a system and feel its fine and safe, others refer to these sytems as "killer" systems due to the risk of legionnaires' disease. A system like that really is a good incubator for legionella bacteria. I ruled out such a system early in the planning stages. I know one big internet DIY site promotes the use of open systems. All of the "pro" sites immensely denounce them.
woodlot
Gold Member
Good question. Years and years ago (like 50) they did use copper for these systems. Now the cost and difficulty in installing have eliminated its use. One of the resources I used to impliment my system also assits people who want to upgrade these older systems with modern controlls. The cu pipe, however, stays.
After all, my barn took over 1/4 mile of pipe. Could you imagine installing that much copper? And checking for leeks? Yikes, not me! I'm pretty sure thats why radient floor heating fell to the wayside so many years ago. Now with PEX everything had changed. The system is now workable, And its simply the best heat available.
After all, my barn took over 1/4 mile of pipe. Could you imagine installing that much copper? And checking for leeks? Yikes, not me! I'm pretty sure thats why radient floor heating fell to the wayside so many years ago. Now with PEX everything had changed. The system is now workable, And its simply the best heat available.
inveresk
Platinum Member
I can see three reasons why metal pipes might be a problem. With 100 metres or so circuit length and very many bends and turns, joints would be serious weakness. With plastic the pipes are continuous under floor with junctions only at the manifold.
I expect the concrete would have a corrosive effect on the copper.
The lag time in the system is in the concrete screed rather than the pipes. Even if you could get heat into the pipes quicker, then the conductivity of the concrete would dictate how fast the room heated up and I doubt if this would be any quicker with metal pipes.
I expect the concrete would have a corrosive effect on the copper.
The lag time in the system is in the concrete screed rather than the pipes. Even if you could get heat into the pipes quicker, then the conductivity of the concrete would dictate how fast the room heated up and I doubt if this would be any quicker with metal pipes.
Sigarms
Super Member
Your stament about the use of a heat exchanger does not come into play for me. I have a "closed system." I'm assuming by your comment that you have what is referred to as an "open system." That one where your potable water is also used for heating. Some people use such a system and feel its fine and safe, others refer to these sytems as "killer" systems due to the risk of legionnaires' disease. A system like that really is a good incubator for legionella bacteria. I ruled out such a system early in the planning stages. I know one big internet DIY site promotes the use of open systems. All of the "pro" sites immensely denounce them. )</font>
Where did you get this information?
Please list ONE CASE where an open system caused "harm".
Please list as well those "pro" sites that "denounced" open systems.
No offense, but please get your facts straight.
Your statement is absolutly ridiculous.
Where did you get this information?
Please list ONE CASE where an open system caused "harm".
Please list as well those "pro" sites that "denounced" open systems.
No offense, but please get your facts straight.
Your statement is absolutly ridiculous.
Highbeam
Super Member
Concrete mixed with aluminum is bad news. The Al is 2+ and the limestone in the concreste is caustic and since opposites attract the aluminum steals electrons.... well, it's not good.