[Greenbuilding] Anyone know about the Legalett Slab System
Lynelle Hamilton
lynelle at lahamilton.com
Sun Jul 16 22:20:58 CDT 2017
Wow, thank you for the detail!
I will have to raise the house up 24-30" in order to be on grade with
the septic at the south side. The other 3 sides will have some variant
of a retaining wall or slope. I have concerns about the Legalitt from
that perspective as well. That and the level of insulation--I've
traditionally done R34 under the slab. They do have a water system
option, but I've not yet found the pipe diameter specs on the website
for it.
I've always thought concrete to be a better transfer medium for radiant
heat. Do you notice a difference with your floor system?
Lynelle
On 2017-07-16 10:58 PM, John Salmen wrote:
>
> Interesting. If a slab is to be used I am a fan of frost protected
> foundations or integrated footing in a cold climate. A lot less ground
> invasive and a lot less concrete. Not so effective here on the west
> coast as we don’t need much depth.
>
> Now ‘if a slab is to be used’ in a consistently cold place heating the
> slab makes sense if there is sufficient insulation below. The use of
> air has a very ancient history – as does water. Air though only
> contains a tiny fraction of the energy storage potential of water.
> They will both transfer heat but what it means practically is that air
> will transfer heat quickly and water will transfer it more slowly.
> From here on it it gets more complicated looking at pumps and fans to
> figure out who is working more efficiently but strong suspicion would
> be that water flow would be drawing less energy (heated to a lower
> temperature, slow pumping velocity)
>
> What is generally more important to me environmentally is both
> minimizing materials and being a bit qualitative about what the
> material is for the job it needs to do. We currently waste a lot of
> materials on buildings. What seems like a good idea is often bad design.
>
> Look at the pictures on the lego slab site. A structural slab can be
> as thin as 3” and work well if reinforced properly. The buildup they
> have with what looks like 2-3” pvc pipe (or in another picture
> galvanized duct would probably require 6-8” of concrete. That is a lot
> of energy intensive material to no structural effect (simply contains
> pipe). Someone could try to make an argument about ‘mass’ but
> typically a well insulated drywalled house with a few tile floors has
> more than enough ‘mass’.
>
> Also a radiant water slab is typically ½” polyethylene pipe classed as
> either a type 1 or 2 plastic – a bit better on the scale than PVC
> which is a type 3 and has long been recognized as not the greatest –
> in comparison.
>
> The most important element is insulation and they are using plastifab
> brand type 1 expanded polystyrene. About 98.8 percent air and 1.1
> percent of some vinyl monomer (PVC) – expanded with pentane. I don’t
> have issues with that so much as it is effective for the job it is
> doing and can go having some life as it is a solid isolatable and
> recyclable material (for some uses). Its wholesale cost is generally
> abound 16 cents a board foot and retails for about 3 times that. There
> are better foams and monomers out there but guess what PVC is cheap –
> so industry uses it. What can we do but be efficient with what
> industry gives us thankful people.
>
> I italicized ‘if you use a slab’ as I’ve eliminated concrete slabs in
> projects as only a footing is required for load bearing elements and
> have used the foam as the floor system with ply sheathing laminated
> over the foam supporting interior walls and finished floors. Radiant
> heating tubes are imbedded in the foam. An FPS footing can be done
> without an integrated slab. Check with your engineer.
>
> Thanks for the opportunity to comment on that.
>
> Best
> John
>
> *From:*Greenbuilding
> [mailto:greenbuilding-bounces at lists.bioenergylists.org] *On Behalf Of
> *Lynelle Hamilton
> *Sent:* Sunday, July 16, 2017 6:23 PM
> *To:* Green Building
> *Subject:* [Greenbuilding] Anyone know about the Legalett Slab System
>
> Has anyone had any experience with this?
>
> Many thanks!
>
> Lynelle
>
> Image removed by sender.
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
>
>
>
> Virus-free. www.avast.com
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
>
>
>
>
> _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/greenbuilding_lists.bioenergylists.org/attachments/20170716/8cf69fbf/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 350 bytes
Desc: not available
URL: <http://lists.bioenergylists.org/pipermail/greenbuilding_lists.bioenergylists.org/attachments/20170716/8cf69fbf/attachment.jpg>
More information about the Greenbuilding
mailing list