[Greenbuilding] Roxul under concrete floor - was exterior wall sheating/insulation

[Christa Carpenter]

Thanks Rob,  I will keep your message and use it to discuss the 
possibilities with my contractor.

Christa

----- Original Message ----- 
From: "Rob Tom" <ArchiLogic at yahoo.ca>
To: "Christa Carpenter" <christa at nbnet.nb.ca>; 
<Greenbuilding at listserv.repp.org>
Cc: "SB Yahoos" <sb-r-us at yahoogroups.com>
Sent: Saturday, March 24, 2007 2:34 PM
Subject: Re: Roxul under concrete floor - was exterior wall 
sheating/insulation


On Fri, 23 Mar 2007 09:06:18 -0400, Christa Carpenter
<christa at nbnet.nb.ca> wrote:

>> will be a 1 storey walkout facing just east of south (in NB Canada) so I
>> plan to put in lots of south facing high efficiency windows and insulate
>> the foundation.  I was wondering what you all would recommend using for
>> insulation.  Would Roxul be good for under the slab as well as the
>> vertical walls?

Christa;

Since none of the usual suspects have yet responded...

The compression resistance (CR) of Roxul's "Drainboard" product is 18 kPa
(~ 2.6 psi) @10% deformation.

For the sake of comparison, the CRs of expanded polystyrene (EPS) (aka
white "beadboard") and extruded polystyrene (XPS) (ie "Styrofoam SM" ) are
69 (10 psi) and 207+ kPa  (30 psi+) respectively at 10% deformation.

If you're not up on your kPa's and psi's... let's assume your floor slab
is going to be 100mm
(~ 4") thick and your live load is 4.8 kPa (100 psf) (typically the design
live load for main level and bedroom level floors are 2.4 kPa & lower but
I have no idea what you intend to do in your basement) so we'd be looking
at something in the neighbourhood of 7.2 kPa combined live & dead load
(unfactored) or about 10.2 kPa factored.

Roxul also makes a "RXL 80" insulation board whose compression resistance
is 27.1 kPa @10%.

Since all of the Roxul board products are "softer" than EPS (ie white
"beadboard") you'd have to take the usual precautions during placement
(both of the board and the concrete) and concrete finishing operations to
ensure that the board does not get crushed . ie Don't walk on it or roll
wheelbarrows full of concrete over it. ie Place moveable sheets of plywood
or OSB etc over the insulation where there will be traffic and don't let
Jake the Rake and his boys run around in the wet concrete.

As as with any insulated slab, the substrate for the slab should be
well-drained/systematically drained to ensure that the insulation stays
dry.


=== * ===
Rob Tom
Kanata, Ontario, Canada
<A r c h i L o g i c   at  c h a f f y a h o o   dot   c a >
winnow the chaff from my edress in your reply