PEX tubes and Termite Pre-Treatment for New Construction
Last Post 16 May 2014 01:17 PM by Rafi. 10 Replies.
Printer Friendly
Sort:
PrevPrev NextNext
You are not authorized to post a reply.
Author Messages
RafiUser is Offline
New Member
New Member
Send Private Message
Posts:57

--
25 Apr 2014 06:01 PM
Hi, This might be a stupid question, but maybe somebody can give me answers anyway. My husband and I will lay the PEX tubes for the floor heating ourselves. Since we are in Arizona climate zone 2, we don't need under slab insulations and most likely will have the tubes attached to a mesh right above the ground (our design is in work, will know details later). Anyway, we will need that Termite Pre-Treatment for new construction before laying the mesh/tubes. Is there any possibility that the chemicals could be aggressive to the material and cause damage in the future since the material might be touching the chemicals on the ground? Thank you.
sailawayrbUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2270
Avatar

--
25 Apr 2014 08:37 PM
Generally, PEX is approved for installation directly within or below concrete slabs including where soil termiticide or pesticide treatment is required (be sure to check with the manufacturer for installation limitations).

http://plasticpipe.org/pdf/tn-39_application_of_pesticides_termiticides_near_pex.pdf

For HR system heated slab-on-grade floors, your minimum under-slab insulation R-value should be 0.125 x (Ti - To), where Ti is your indoor design temp and To is your outdoor design temp (in units of deg F).

Having this minimum under-slab insulation R-value tends to keep the downward heat loss to about 10% or less of the total heat supplied to the floor. This is typically considered a reasonable tradeoff between insulation economics and heating system efficiency. More insulation will improve your efficiency, but will also hurt your pocket book more...so there is a ROI to be considered here.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
jonrUser is Offline
Senior Member
Senior Member
Send Private Message
Posts:5341

--
25 Apr 2014 09:24 PM
No insulation means more thermal mass which means even slower response time to changing weather conditions.
LbearUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2740
Avatar

--
25 Apr 2014 09:51 PM
Most companies will use Termidor SC for termite soil treatment, it is made by BASF.

You should be putting down 4" of compacted AB underneath the concrete slab. I would also put down some poly ABOVE the AB and just underneath the slab. It will help with termites because they can't chew through poly. Also, get some termite sleeves on your in-ground slab plumbing as it comes out of the slab and transitions into the home.




FBBPUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:1215

--
26 Apr 2014 10:11 PM
Sailor - is To outside design or ground temperature?
sailawayrbUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2270
Avatar

--
27 Apr 2014 10:48 AM
FBBP, this equation comes from Sigenthaler's Modern Hydronic Heating and is specifically for slab-on-grade. As such, To is the outside air temp at design load conditions. Since this R-value is minimum recommended, we bump up to the standard thickness that meets or exceeds this value.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
LbearUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2740
Avatar

--
27 Apr 2014 11:52 PM
Would it be safe to say that 2"-3" of EPS underneath a slab-on-grade in Zone 2 would be a waste of money in terms of ROI for energy savings?


sailawayrbUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2270
Avatar

--
28 Apr 2014 08:07 AM
Well Lbear, the equation indicates that you would need about a 40F delta temp (Ti-To) to require a R5 minimum or about 1” of EPS.  So 2"-3" would likely be too much, but 0" would likely be too little.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
RafiUser is Offline
New Member
New Member
Send Private Message
Posts:57

--
06 May 2014 10:32 AM
Thank you all for your feedback.
The pest control company we would like to hire for spraying the pad says it doesn't harm PEX pipes/tubes. And they said that we have to lay the tubes first, then they come to spray. I guess we have no other chance than doing it that way since laying tubes on 5000 sq ft takes couple days including testing the tubes etc.. Once termite chemicals are sprayed, the concrete needs to be poured within 48 hours or so. Still don't really feel good about it though.

In regards to the under-slab insulation we understand about the heat loss. But we had our floor heating design made by local engineers and they said that in our climate zone 2 it would have been an overkill if we did that too. We are in hot Phoenix area and the average person wouldn't think about radiant floor heating at all. Anyhow, there are months where heating is necessary even in Phoenix. Once one knows or experiences the difference between forced air-heating and radiant floor heating there is no question (at least not for us) that we will do the extra effort to have it installed. Btw... I've experienced so many different ways of heating living areas like oil, gas, wood, etc., but forced-air is by far the worst way to heat and waste of energy. But of course that's my opinion only.
ChrisJUser is Offline
Basic Member
Basic Member
Send Private Message
Posts:277

--
06 May 2014 12:30 PM
"but forced-air is by far the worst way to heat and waste of energy. But of course that's my opinion only."

I used to live in a house built in the late 60's that had forced-air oil heat, it was terrible, loud, not comfortable.

4 yrs ago I moved into a new construction home with a multi-stage GSHP. Totally different then the old house. In a well insulated house with a well designed duct system, the comfort level is very high. First stage sends only 800 cfm of warm air, I can't tell it's on unless I am 3-4' from the largest return duct.

As for waste of energy, I heat 2000 sq ft for about 3-4 dollars a day. I am in Rhode Island.

To me putting in a radiant slab without some amount of insulation under it is wasting energy. Even in Phoenix. My opinion.

Chris
RafiUser is Offline
New Member
New Member
Send Private Message
Posts:57

--
16 May 2014 01:17 PM
No I don't think so, that the used chemicals could be aggressive to the material and cause any kind of damage in the future, because the chemicals are formed on the basis of compatibility issues with material. I have also done a project with termite inspection sacramento team as I am a Chemical Engineer and the solvents used by me was totally secure.


Jackpitter: Did you use Premise or Termidor or something else? Thanks.
You are not authorized to post a reply.

Active Forums 4.1
Membership Membership: Latest New User Latest: hudson2000 New Today New Today: 0 New Yesterday New Yesterday: 2 User Count Overall: 34707
People Online People Online: Visitors Visitors: 173 Members Members: 0 Total Total: 173
Copyright 2011 by BuildCentral, Inc.   Terms Of Use  Privacy Statement