New garage time!

[civilian]

Yes, very good pic Jon.

This clearly shows how much space sweep elbows require.

Is that a 5" pour? Hard to tell in a pic.

Good example of a very tidy setup!!!

Thanks. Yes 5" pour. When the contractor called for inspection, inspector said you are good to go based on seeing his prior work. And yes I have many pictures of that floor. Jon

 

[Wobblin-Goblin]

Been in the flatwork business for 21 years. I bought my first power screed 19 years ago and it's been 18 since I got rid of it.

 

[ovrszd]

^ understandable logic, but what perspective were you really trying to help him gain here? You definitely want to pressurize your PEX during the pour. You *might* get lucky and see some bubbling up through wet concrete if you did get a leak. You could then box that area out, finish the pour, and do a local pex and concrete repair afterwards.

But more than likely, you will not get a leak. It feels darn good to get through the pour and finishing work, and see full pressure on your gauge still. In my township, it was actually a code and permit requirement to keep the PEX pressurized during the pour.

If you are talking to me, I wasn't trying to help him gain any perspective. I was simply offering logic.

In this particular case the pex is in the top 2" of the pour. It's impossible to see a bubble, then box it out, and fix later. Impossible.

My point is/was if you detect a leak because you have pressurized what can you do about it? In the end, nothing. You don't have time.

I'm not opposed to pressurizing. If it is code, which I have no idea why, go for it. If it "seems" like the right thing to do, go for it.

 

[ovrszd]

Been in the flatwork business for 21 years. I bought my first power screed 19 years ago and it's been 18 since I got rid of it.

Can you offer tips, hints on what the OP should do here? Thanks.

 

[MossRoad]

From here:
How to install PEX Tubing in a concrete slab

Types of concrete slabs with radiant floor heating
Thick slabs
Thick slabs are concrete slabs with an overall thickness of 4-6" or greater and can be either grade level (slab on grade) or below grade (i.e. basement foundations). All thick slabs can be categorized into:
Reinforced slabs – where welded wire mesh or rebar is used to reinforce the slab.
Non-reinforced slabs – where no reinforcement is added.

While reinforcement itself does not affect the radiant floor heating system, it determines placement of the PEX tubing in the slab, which in itself is an important factor. Unless special design considerations require otherwise, the tubing should always be positioned on top of the reinforcement, in order to stay closer to the surface of the slab.

If using welded wire mesh, you may want opt for sheets rather than rolls whenever possible. They are noticeably easier to install and provide a flatter surface. The main downside is that the sheets have to be tied together.

Optimal depth of PEX tubing in the thick slab is considered to be in the 1-2" range and, whenever possible, should not be deeper than 4" for the following reasons:
Placing tubing too deep in the slab will increase response time, which means it will take longer for the floor to reach the desired temperature, will result in increased BTU load, require more energy and possibly will require larger tubing diameter.
Concrete height above PEX adds additional R value, and while it’s minimal in most instances, more energy would be required to heat the topmost surface.

Since in non-reinforced slabs tubing is generally positioned at the bottom (secured with foamboard staples or PEX rails), their thickness should not exceed 4-5". Otherwise, the system will not run efficiently. The only remedy for a deep slab is to install reinforcement and position PEX tubing on top, closer to the surface.

 

[fatjay]

I don't think the point of pressurizing pex is for leak detection, stopping the pour so you can fix a leak. I think it's for protection against crushing/kinking. Even if it's not much, it's something, it doesn't cost you anything, so why not? Who has time to keep an eye on a gauge during a pour?

The pour crew will likely be 2 guys 60+ who have been doing it for 40 years and 4 guys who are younger. First truck at 8am, 2nd truck at 11am, cleanup truck at 2pm. What day still not sure, it came down in sheets today. Hoping for next saturday.

Today was sidewall insulation, pex cleanup, and pour inspection. Now that all pex is in place I could go around and cut the perimiter wire back 2" and put in insulation, caulked it to the wall to keep it from moving during the pour and kept it at the 6" mark. The slab is more than 6", it's 6" up the first block, but since I hit it all with the jumping jack and lost .5-2" in areas there will be extra thickness.

That pex is a bear to work with, but i managed it. with the wire pushed down to the bottom the elbows come just out of the surface. I'm happy with how it came out, but I'm still watching for places it could potentially go wrong.

 

[fatjay]

From here:
How to install PEX Tubing in a concrete slab

This is where I started to get my information, then searched around and found a lot of supporting information, so I decided to go with it. I posted that link up 5-6 pages ago. I know pouring isn't easy, I've done my share. Adding pex and not being able to walk on it adds complications. But I don't think it's impossible.

 

[ovrszd]

From here:
How to install PEX Tubing in a concrete slab

I think the OP posted this earlier. I understand that he's trying to follow the advice he's been given by this site. I've never heard that before.

I've saw the pex tied to the rebar with the rebar on chairs placing it in the middle of the slab. I understand the OP is using the mesh to determine his spacing which is necessary because his rebar is on 24" center.

My biggest concern is dealing with the pex during pour with it that close to the surface. If he was pouring using a pumper truck I wouldn't be quite as concerned. Without one the majority of this wet concrete will be moved with come alongs.

If I were his neighbor I'd show up to help. You can't get too much help on a project like this.

 

[ovrszd]

This is where I started to get my information, then searched around and found a lot of supporting information, so I decided to go with it. I posted that link up 5-6 pages ago. I know pouring isn't easy, I've done my share. Adding pex and not being able to walk on it adds complications. But I don't think it's impossible.

I'm with you in spirit. As I said above, if I were your neighbor I'd show up to help.

I know this has been a tiring project. Hang in there. Don't weaken.

 

[fatjay]

I wanted a pumper truck, but the price was just to unreasonable. Truck rental is $250, concrete is $100/yard, totaling $1250. Pumper is an additional $1357. If it was an additional $500, maybe I could justify it.

 

[EddieWalker]

If you are talking to me, I wasn't trying to help him gain any perspective. I was simply offering logic.

In this particular case the pex is in the top 2" of the pour. It's impossible to see a bubble, then box it out, and fix later. Impossible.

My point is/was if you detect a leak because you have pressurized what can you do about it? In the end, nothing. You don't have time.

I'm not opposed to pressurizing. If it is code, which I have no idea why, go for it. If it "seems" like the right thing to do, go for it.

Since I've never done a heated floor or worked with PEX in this manner, I'm just kind of guessing here. Why not fill the PEX with water that has a die in it that would be easy to see if there is a leak? Or is this possible?

 

[pmsmechanic]

I just read all 27 pages. Well worth the read in my books!

I was just thinking to myself before I read the last post that a pumper truck in this situation would sure be nice. Then I read your last post. I concluded with the thought that for $1357 a pumper truck would still be nice. I can relate to your internal debate as I'm wired the same way.

What I like about the idea of a pumper truck is that the pump can put the concrete where you want it and leaves you with the time and energy to make sure your concrete is level and that your pex/rebar etc stays in place. It will also help ensure that your pex doesn't get damaged. Honestly if you figure the price of the pumper truck and what it gives you for me it would be a close call. The price of your help and how tired you are going to be at the end of the day is worth something too.

Some more for you to think about....

Added a note of interest. I've been to Haiti several times to help drill water wells. They used to carry the concrete everywhere in bucket brigades because labor was cheap. Lately they've been using cement pumps. Not the large trucks we have but just a cement pump on a small trailer. They lay pipe out to where the cement is needed and pump it to the pouring point. If you could find something like that it could be a cheaper option.

 

[dodge man]

A little off topic and I’m not being critical of the OP, but what is the deal of in floor heat. I see it being done a lot, I get it inside the house, but I don’t understand it in a garage or shop. I’ve got a Reznor heater in my 28 x 30 shop, it will heat it up from 40 degrees to 60 degrees in about 10 minutes in the dead of winter. It’s the kind that hangs in the corner and was maybe $1500 installed.

Good luck on the pour, it sounds like you have some experienced help and plenty of manpower.

 

[pmsmechanic]

A little off topic and I知 not being critical of the OP, but what is the deal of in floor heat. I see it being done a lot, I get it inside the house, but I don稚 understand it in a garage or shop. I致e got a Reznor heater in my 28 x 30 shop, it will heat it up from 40 degrees to 60 degrees in about 10 minutes in the dead of winter. It痴 the kind that hangs in the corner and was maybe $1500 installed.

Good luck on the pour, it sounds like you have some experienced help and plenty of manpower.

Let me put it to you this way. Have you ever worked under a vehicle off of a heated floor? It's so nice and warm down there. With forced air the floor is always colder than the air. With floor heat the floor is always warm. The only downside I've seen up here in Canada is if you get a nice warm chinook right after a cold spell. It takes a few days for the thermal mass of the concrete to cool off enough so that the shop isn't too hot. An added bonus is that any water on the floor evaporates quickly. There's no fan to blow any dust all over the shop. I'm sure there's other benefits but that's all I can think of for now.

 

[dodge man]

I guess in my mind it’s not worth the cost. I lay on a creeper or pad on my floor so I don’t notice the cold.

 

[ovrszd]

I wanted a pumper truck, but the price was just to unreasonable. Truck rental is $250, concrete is $100/yard, totaling $1250. Pumper is an additional $1357. If it was an additional $500, maybe I could justify it.

Oh wow!!! We have access to one semi local, he's $500. When they poured my shop they brought one in from $100 miles away. He was $800.

Saves a tremendous amount of labor. In the case of this pour, I'm afraid there is going to be a LOT of dragging concrete. With the rebar/mesh/pex setup you can't rev up the truck and squirt the concrete to gain distance. It will have to be dropped off the chute gently.

 

[ovrszd]

Since I've never done a heated floor or worked with PEX in this manner, I'm just kind of guessing here. Why not fill the PEX with water that has a die in it that would be easy to see if there is a leak? Or is this possible?

I don't think it is going to matter. As the OP already realizes, he can't stop and fix a leak. His idea of minimizing the chance of puncture by having pressure has some merit. With that said, pex pipe is extremely durable and pliable. For example, when his slab cracks, the pex will survive it.

 

[ovrszd]

A little off topic and I’m not being critical of the OP, but what is the deal of in floor heat. I see it being done a lot, I get it inside the house, but I don’t understand it in a garage or shop. I’ve got a Reznor heater in my 28 x 30 shop, it will heat it up from 40 degrees to 60 degrees in about 10 minutes in the dead of winter. It’s the kind that hangs in the corner and was maybe $1500 installed.

Good luck on the pour, it sounds like you have some experienced help and plenty of manpower.

I have hydronic in-floor heat in my house and my shop. House thermostat on 71F. Shop thermostat on 68F. I am in my shop every day. During bad weather I may be in my shop 12 hours. I expect everything in my shop to be warm.

My shop is 1872 sqft with 14ft ceiling. My house including one car garage (which is heated) is 2450 sqft with 9ft ceiling. We run 3 propane tankless heaters. One for each floor heat system, one for domestic hot water. We burned 1050 gallons of propane the last 12 months.

 

[ovrszd]

Let me put it to you this way. Have you ever worked under a vehicle off of a heated floor? It's so nice and warm down there. With forced air the floor is always colder than the air. With floor heat the floor is always warm. The only downside I've seen up here in Canada is if you get a nice warm chinook right after a cold spell. It takes a few days for the thermal mass of the concrete to cool off enough so that the shop isn't too hot. An added bonus is that any water on the floor evaporates quickly. There's no fan to blow any dust all over the shop. I'm sure there's other benefits but that's all I can think of for now.

Excellent post. Only drawback is overheating during large temp swings as you described. We notice that more in the house than in the shop. There's no heat more comfortable to work in or to live in. It's radiant. Everything in the heated space is warm, not just the air.

 

[ovrszd]

I guess in my mind it’s not worth the cost. I lay on a creeper or pad on my floor so I don’t notice the cold.

I would contend that you could maintain 60F temp in your shop with floor heat cheaper than you could adjust your temp from 40 to 60 back to 40 each day with your Reznor.