WIRSBO JOIST TRAC

Ron Huber

Not much wind or snow load under our radiant floors, try pulling down a plate with 8 roofing nails shot from a nail gun.

Kent D.

WIRSBO JOIST TRAC

I'm a homeowner installing staple-up radiant in an addition to my house. I'm using the Wirsbo 'joist trac' product. I'm hoping that some of you are familiar with this relatively new extruded aluminum product - it seems that once I have the plates up the tubing will snap in place pretty easily. I need to install 450 plates and there are 10 pre-drilled fastener holes per plate - 4500 fasteners!!

Three questions - 1.) can I use standard 3/4" steel screws to install these plates? 2.) is there a better/easier fastener to use? and 3.) do I need to put a fastener in each hole?

Thanks.

Jamie_6

They are there for a reason!

I know that is a lot of screws put all those holes are there for a reason! We just finished a job that had 40 boxes of joist-Trac. Over 8000 screws. Man did our arms hurt! I have heard that people (shoot) them in with Staples and an air gun!

Good luck

John Felciano

Plates

we use automatic screw guns with self tapping screws.We don't worry about the predrilled holes.We also work off rolling staging and yes my neck and arms hurt at the end of the day.Much better work for the apprentices.

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Ron Huber

Joist Trac

we use a roofing gun with 3/4" roofing nails. It is fast,you do not have to hit the pre-drilled holes, we made up a little jig that holds the plates evenly along the joist, then shoot it in, holds great, just did an 11,000 sq. ft. house, cannot imagine screwing that many plates with screw gun.

Marc Sherby

Onix by Watts Radiant

When you use Onix hose from Watts Radiant you won't need plates. Staple's right up to the subfloor. Saves a lot of time and arm!

heatboy

Why..........

don't you need plates? Is the output from rubber better than that heavy extruded aluminum? Please explain. With all of that surface area the extruded plates provide, it seems they would transfer quite a bit more heat and dramatically lower water temperature requirements.

hb

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Mike Kraft

plates

Could'nt agree more with heatboy.Extruded plates are now offered by 6 companies(that I know of).The industry is seeing the light bulb!

Lower temperatures,quicker reaction,larger surface area and an intimate communication with the tube and the plate.It's an obvious no brainer what the differences are with a bare tube (or rubber hose) stapled to the underside of a subfloor and what parallel extruded aluminum plates holding tube can be!

cheese

joel_14

no plates

If you don't use plates your water temp will need to be higher ,to get the same amount of heat from the system. This defeats the whole purpose of radiant which is to lower the water temp as much as possable.

Mark Hunt

Good question


now tell me why Pex NEEDS plates. Could it be that plates are REQUIRED because of the expansion noise that Pex makes?

So if I got plates I can LOWER water temps thus avoiding those nasty expansion noises that Pex makes? Hmmmm???

Or maybe we'll do a suspension job so the Pex doesn't touch anything? But then the temps go up! I thought that LOWER water temps were better?

It's all physics, and Uponor didn't invent them. Neither did Heatway.

We can all meet in the middle ground and say that Pex-Al-Pex is the best of both worlds, Pex with low expansion.

As far as I can see, the plastic companies HAD to come up with a way to lower water temps to counter act the expansion of their tubing. BTU's are BTU's no matter what the water temp is. I don't care what the efficiency of your boiler is or your distribution method, BTU requirements are determined by the way the structure is built and insulated. Build it tight and vent it right and you lower BTU requirements. That means I can lower the water temps regardless of whose tubing I was using.

I have MILES of Onix tubing out there and MILES of Pex and Pex-Al- Pex.

What a bunch of happy customers!!

Mark H




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Mark Hunt

Good question

> don't you need plates? Is the output from rubber

> better than that heavy extruded aluminum? Please

> explain. With all of that surface area the

> extruded plates provide, it seems they would

> transfer quite a bit more heat and dramatically

> lower water temperature requirements.

>

> hb

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 103&Step=30"_To Learn More About This Contractor,

> Click Here to Visit Their Ad in "Find A

> Contractor"_/A_




now tell me why Pex NEEDS plates. Could it be that plates are REQUIRED because of the expansion noise that Pex makes?

So if I got plates I can LOWER water temps thus avoiding those nasty expansion noises that Pex makes? Hmmmm???

Or maybe we'll do a suspension job so the Pex doesn't touch anything? But then the temps go up! I thought that LOWER water temps were better?

It's all physics, and Uponor didn't invent them. Neither did Heatway.

We can all meet in the middle ground and say that Pex-Al-Pex is the best of both worlds, Pex with low expansion.

As far as I can see, the plastic companies HAD to come up with a way to lower water temps to counter act the expansion of their tubing. BTU's are BTU's no matter what the water temp is. I don't care what the efficiency of your boiler is or your distribution method, BTU requirements are determined by the way the structure is built and insulated. Build it tight and vent it right and you lower BTU requirements. That means I can lower the water temps regardless of whose tubing I was using.

I have MILES of Onix tubing out there and MILES of Pex and Pex-Al- Pex.

What a bunch of happy customers!!

Mark H




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Wayco Wayne

We had this discussion

at Wetstock one. Onix may have a better heat transmission than Pex in a staple up situation, but it is not a replacement for extruded joist plates which are the best at transmiting heat into a floor. (I will check my files and see if I have ME's infrared pictures of heat transmission) I have always decided which method to use based on what kind of boiler. What good is lower temps in the floor if you then have to protect the boiler from low temps? If I have a condensing boiler then plates make perfect sense. If I have a cast iron beastie I might as well go staple up. I feel more confident of ability for capacity with plates but they are defineitely pricey and add cost to the job at a considerable rate. WW

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heatboy

Also, good questions.

No PEX, or anything else for that matter, need plates to control noise. I can circumvent any noise issues with the reset controls my projects utilize.

Since virtually 100% of the boilers I prefer to use are capable of running at low temperatures , it is critical to have distribution and emitter systems that are efficient and allow water temperatures as low as possible. The only way to attain the low temperatures required for the use of low temperature heating equipment, in joist bays anyway, is with the use of extruded plates. Yes, in my radiant world, there is no other way to do joist bay heating.

hb

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Earthfire

fasterners

IMHO the only fasterner to use in a residential plate install is a screw,and NOT a self-drilling Tek-Screw. The wire of a staple is too thin to match the expected life of the building (50+ years) and plate. Steel against aluminum does have a galvanic corrosion issue. As for 3/4" roofing nails, they have little holding power in plywood if they do not penetrate thru the sheet. With roofing nails, over time the weight of the plates and the constant motion of the floor flexing and the aluminum expanding and contracting will cause the nails to back out of the subfloor and the plates will loose contact with the floor. One of the major reasons that shingles blow of of roofs is nails thatdo not penetrate the plywood deck properly. By the way this does not apply to solid sawn lumber just the laminated materials. Question: Why would anyone use rubber hose? If rubber is good ,why do washing machine hoses blow out? Why do we replace the hoses on our car and truck cooling systems? ETC.

heatboy

Boiler efficiencies.

Wayne,

I understand the logic behind your statements about boiler protection. What about boiler efficiencies, though? We can certainly agree that a boiler running at 140° is substantially more efficient than a boiler running at 180°, right? So, with extruded plates (ThermoFin are my favorite) we can save quite a bit of energy, and our clients money, over the years when plates are utilized. If I look at the long term performance and efficiencies, using plates seems to be, to me anyway, the best thing I can do for my client.

hb

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hot_rod

It's a heat transfer game

Nothing more nothing less. The goal it to raise the floor temperature to a temperature to offset the building heat loss. Most would agree 85 floor surface temperature would be the maximun comfortable temperature. With this number in mind, really the floor doesn't care HOW it gets to that temperature. Plates, bare tube, wood fueled fires beneath (Roman vintage method) The biggest challange will always be the floor covering R-value.

The transfer plates increase the transfer rate, period. My study indicated both speed and, to an extend, stripping are the main benefits of transfer plates.

Yes it does take more energy to raise a gallon of water to 140 or 160. BUT there is more energy available, to be used, in the higher temperature water, as energy can never be created or destroyed. To me the standby loss of the hotter water is the biggest factor. Especially in a poorly insulated boiler with a flue through the roof and combustion air at the base (chimney effect)!

Certainly heating the structure with the lowest possible temperature, and the most efficient appliance make sense from energy use standpoint. However it remains to be seen if the low temperature appliances will in fact prove to be the least expensive device, to own and operate, after 5, 10, or 15 years. Repairs, maintenance, and product life expectancy will need to be factored in, as well as upfront cost difference. If your devise develops an appetite for ignitors, circuit boards, inducers, lockouts, etc. repair costs will easily over come fuel savings, at least in my experience

hot rod

David Van Wickler

ASHRAE

It comes down to conductive surface area (plates contacting the sub floor) versus convection and some conduction (onix or pex stapled directly to the subfloor with an air gap).

Plates increase the contact surface by extending the avaliable surface area of the tubing.

Pex tubing, when stapled directly to the sub floor has but a thin line contact, basically zero conduction capacity and relies on convective air currents. Onix, through hundreds of staple squashing, increase the surface area wherever the tubing is squashed by a staple. Heatboy, a long time ago, asked if there was a reduction in flow due to turbulent/increased flow resistance. additionally, the localized hot spots due to increased surface contact does effect wood floor stability. Seen it dozens of times with both methods of installation. Plates can do a job on wood floors. Any wood floor installation should utilize Wirsbo or tekmar thermostats with floor sensors that allow high temperature limits.

How much more efficient is Onix versus staple-up pex? I personally believe the heat output are not apples to apples. There are too many variables in either method to properly support either method.

Now, plates on the other head, if supporting the tube properly (i.e. good surface contact) will provide conductive heat transfer and is mathematically possibly to verify the heat transfer potential. Dale Pickard has done some previos work in FEA computer generation. I have an engineeing friend working on modeling a profile that I presently am patenting.

The plates are the choice when heat outputs require either plastic or rubber to operate at elevated temperatures. Radiant floor heating should operate at the lowest water temperatures with a system that is economical and can have a reputation hung around it by the installer.

Does pex staple up work? Yup, and so does rubber steam hose. Why did Wirsbo switch to the extruded aluminum plates when for so long the only folks promoting the expensive extrusions where Dale's and Radiant Technology (RTI)? Because they were the only two companies that realized their reputation, the reputation of the installer, and the guarantee to the customer could only be acomplished with a product that had irrefutable (sp?) heat output versus water supply temperatures.

Another question. If rubber steam hose is so good, why is there only one company in the entire world selling it to the radiant heating industry?

David Van Wickler

EFFICIENCY TO RAISE WATER TEMPERATURE

"Yes it does take more energy to raise a gallon of water to 140 or 160. BUT there is more energy available, to be used, in the higher temperature water, as energy can never be created or destroyed. To me the standby loss of the hotter water is the biggest factor. Especially in a poorly insulated boiler with a flue through the roof and combustion air at the base (chimney effect)!"

I would agree that it takes more initial energy to raise water from 140 to 160. But it's the delta T, and for asystem operating at 20 degrees or 10 degrees it doesn't take alick more energy. Standby losses - sure. But if energy use is you concern then outdoor reset or any reset will wipe that issue away.

Radiant is more efficient due to infiltration/exfiltration, glazing losses are less due to long wavelength radiant versus hot baseboard and natural convection or scorched air, MRT and air temperature versus comfort and ductwork losses versus little pipes carrying water, etc....

A staple up at 160F is nearly as efficient as plates and 135F.

It boils down to several additional design constraints that plates and staple-up can overcome. Even baseboard can be encorporated in a system that can operate on one water supply temperature and co-exist with several installtion methods.

DVW

David Van Wickler

NOT ALL TEN

Screw the ends and two in the middle.

SIX is enough - To start I screw one in each trak (middle one) and line the plates up by eye. The one screw in the middle allows the plates to rotate around the screw and when the tubing is installed the plates will self align. Get the helper to run the rest of the screws in as noted above and insulate.

DVW

Wayco Wayne

Interesting points

I didn't think about the zone between 140 and 160. However... I ususally have the joist heating without plates on constant circ with outdoor reset. How much of the time would we be all the way up to 160, and how much time would we be down at 140. Washington DC is not ususally that cold all Winter. What kind of payback do you get under those conditions towards the payback for the investment of plates. I just had a customer not go with radiant because of costs. He needed 900 plates. Thats about 4500 extra dollars. Would that have made the difference in his decision? I had specified a condensing boiler so the plates made perfect sense. Thanks for the input. You're making me think. (ouch)

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heatboy

Hello David!

It's good to see your words here again. I, for one, have missed them!

"A staple up at 160°F is nearly as efficient as plates and 135°F." I'm not sure what you mean by that, David. I do know that 135° will be in or near the condensing zone all of the time and a 160° will hardly ever be in that zone. My statement was primarily geared towards condensing boilers, but conventional will still be more fuel thifty at the lower water temps, due to all of the factors that come into play with boiler efficiencies.

The cost of the plates are just that, the cost of the plates. Are plateless systems "good enough" for some applications? Sure, but ........

Elitistly yours ;-),

hb







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John Felciano

HEY!

DVW good to see you on the wall again!..The RPA wasn't quite the same without you there.

For those that were there Dale has a whole bunch of new plates he's developing.Some really cool stuff with some very serious possibilities.

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David Van Wickler

Efficiency of plates

Is measured by the return temperature for sure when you look at the boiler efficiency. Condensing will occur if outdoor reset is utilized for both staple up and plates. I would realize a small difference in design water temperatures at warm outdoor temperatures and progressively (proportionally) greater water supply temperature difference as the load increases. So I would have to look real hard at the knee of condensation, subtract the time difference and probably realize that the difference in energy saving would be due to the low mass design more than the difference in supply water temperatures between plates or no plates.

If your designing staple-up to 160F your asking for trouble.

Design to 130-140 and use plates where water temperatures are too higg for tubing alone.

Or, just use plates along the outside wall and no plates in the middle. The heat loss occurs along the perimeter anyway.

Basket weaving at it's finest!!

Troy_3

Staple gun

We have stapled all our underfloor jobs for the last two years. It is much faster and I feel much more secure. We had a couple screwed jobs fall out a couple years ago. It took 2-years to see it happen. With time I see the screws fall out. Probably from being stripped when installed. Screwing into a 5/8" or 3/4" plywood doesn't allow much tread holding- was my conclusion. Maybe my techs were just too aggressive I don't know. What I do know is taking down insulation and rescrewing and then reinsulating is not a fun or profitable task. We have not seen any stapled plates come down yet.