need pre sleeved or components to sleeve and insulate 3/4 inch pex-A

archibald tuttle

i've got to bury half a dozen 10 foot lengths of pex for both domestic and hydronic service under slab that is in conditioned space and this is literally the first time i'e had to do that where an inspector has to sign off (At least on the domestic runs). it looks to me like the domestic insulation requirement is R-3 for the hot water. there are inexpensive assemblies presleeved in corrugatd HDPE that look pretty rugged but have no insulation (although they describe themselves is "insulated") e.g. https://www.homedepot.com/p/PLUMBFLEX-Pre-Sleeved-PEX-3-4-in-x-300-ft-Red-HDPE-Corrugated-PEX-A-Tubing-with-Insulated-Sleeve-Commercial-and-Residential-Use-HPSP-S56522/330007165

now I honestly think that for short runs this would be OK from a performance perspective even for heating pipe (except that one isn't barrier tubing) because neither the pex nor the HPDE sleeve are highly conductive material and there would actually be air between the two for most of their diameter and the lengths and thus loss we're talking is quite limited. But I don't think the hard headed inspectors are up for applying that kind of thinking compared to code.

there are preinsulated versions of 3/4 inch available that I assume are OK for burial and to come through the slab, e.g. uponor: https://www.supplyhouse.com/Wirsbo-Uponor-F6040750-3-4-Pre-Insulated-AquaPEX-Tubing-100-ft-coil

but they don't have the same highly protective corrugated sheath. There are some pretty expensive versions that do combine insulation and protective sheath that are overkill and a half for this project but nice product, e.g. rehau insulpex * https://www.rehau.com/us-en/mechanicalplumbing/technologies/radiantallfh/pre-insulated-pex-piping

but it does not appear to be available smaller than 1".

then I could do it myself with armaflex tuffcoat. https://www.armacell.com/sites/default/files/2025/10/21/ArmaFlex%20Tuffcoat%20-%20Product%20Brochure%20-%20en-GB.pdf

it seems to say that it is available in 6M rolls although I can't find anyone selling it. I don't think it is split but I'm not sure. at the lengths i'm dealing with I can buy straight pipe and pull it through fairly easily and while it is meant to evoke a certain toughness it looks nothing like as tough as corrugated sleeves.

you can buy the corrugated sleeves independently so i could use some armaflex and then slide it into a sleeve. e.g.

https://www.homedepot.com/p/TekTube-1-5-in-x-100-ft-Flexible-Corrugated-Red-HDPE-NON-Split-Tubing-Wire-Loom-Non-Metallic-Conduit-RHDPENS112100/333298321

it just strikes me odd that there isn't an LCD product that splits the difference on some of these properties for short runs under conditioned space and is readily available vs. the wood boiler or industrially oriented burial stuff. any direction anyone can point me?

thanks, brian

*in the cases of the presleeved pex-A i'm assuming that the pipe in them is approved for domestic water although that could be a false assumption. ironically, some barrier pex is not approved for domestic applications although it is the same quality of tubing that the same manufacturers offer with domestic approval but apparently they have to go through a separate certification process and since it is principally aimed at hydronic service they don't bother to get the domestic approvals.

archibald tuttle

got off the phone with armaflex and they recommend this product. it is code compliant thickness/r-value for hot water and from what I can understand has a somewhat robust exterior shield that can be direct buried, nothing like the HDPE sleeves but better than straight armacell product. and the "tuffcoat" product is apparently more oriented toward above ground UV protection.

still about the same money or less to put regular armaflex into corrugated hdpe albeit I'd have to do a few 20 ft. lengths to see if it is easily possible and worth the trouble to get into the sleeve. the corrougated sleeves i'm seeing readily available top out at 2" (maybe ID although there are no reliable specs) and 3/4 pex plus 1/2" insulation is going to be 1 7/8 inches. was thinking maybe a finger trap pull on pex inserted into armaflex would get that done on the end of and electric fish?

hot_rod

you will need some sort of rounded end on the pex to pull it through. And talcum powder.

I remember the EcoPex coils came with a rounded end cover for pulling