[CANUFNET] Anyone have experience with various weed barrier fabrics?

[Cybulski, Cat]

Some Background: 
A contractor installed 3 oz woven polypropylene landscape fabric in a
large, irrigated, raised median, whereas the contract specs called for 3
oz spunbonded polypropylene. Spunbonded was specified due to its better
air and water permeability (min. 100 gal/min/sf) whereas the woven
material has less than 15 gal/min/sf. The planter has a drip irrigation
system, and to aggravate the matter, the irrigation lines were laid on
top of the woven material. Water is pooling on the tarp-like woven
material. 
The contractor refuses to replace the non-approved material with the
spec'd material, claiming it "exceeds" the specifications. It may exceed
the spec in terms of strength, but the critical characteristic of
permeability has been compromised. 
The questions are: 
1) Will the woven, less permeable material cause problems with plant
growth and survival (trees and perennials), or can we live with it -
with the drip lines on top if it? 
2) What are your experiences with spunbonded (or non-woven) weed
barriers vs woven? 
Thanks

C. Cat Cybulski, R.P.F.
Area Forester
Natural Heritage and Forestry Services Section
Transportation and Works
Regional Municipality of York
(905) 895-1200 ext. 5275
Toll Free:  1-877-464-9675 ext. 5275
www.york.ca

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.web.net/pipermail/canufnet/attachments/20091029/3d2e9cde/attachment.htm>