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Weed Barrier: Spunbonded vs Woven?
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Posted by casia z4-Caledon, Ontario (My Page) on Thu, Oct 29, 09 at 15:58
Some Background First:
A contractor installed woven 3 oz polypropylene landscape fabric in a large, irrigated, raised planter, whereas the contract specs called for 3 oz spunbonded polypropylene.
Spunbonded was specified due to its better air and water permeabilty (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 |
Follow-Up Postings:
RE: Weed Barrier: Spunbonded vs Woven?
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| Why was a more permeable product specified, was it something to do with the plant choice? If the plants specified require a free draining situation and the barrier installed interferes with this it should be changed. |
RE: Weed Barrier: Spunbonded vs Woven?
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- Posted by bboy USDA 8 Sunset 5 WA (My Page) on
Sun, Nov 1, 09 at 16:48
| You already know what you need to know about the fabric: the water is not passing through it fast enough for you. The critical problem is that the contractor is refusing to replace it with the stuff you want. Guess you may have to make other arrangements for getting the job done right, unless you are able and willing to come up with some way to get them to comply with the specifications. |
RE: Weed Barrier: Spunbonded vs Woven?
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- Posted by bahia SF Bay Area (My Page) on
Sun, Nov 1, 09 at 20:58
| Do you also have bark mulch on top of the weed barrier, which can help absorb the water and release it more slowly? I installed a garden with the same less permeable type of weed barrier, and initially it did pool a bit, but after I mulched it with 3 inches of coarse bark, (ground up tree trimmings, actually), it has worked out fine. I installed the less permeable barrier, even though it was over mounds with slopes, because I needed the extra strength to resist weeds such as Oxalis pes-capri and Cynodon dactylon from breaking through. The drip irrigation lines were also installed on top of the weed barrier. Four years later the garden is doing just fine, and I don't regret having made the choice I did, although initially I was a bit worried that it would be a problem. If you are also dealing with weeds that are perennial and can easily break through the more permeable barriers, it makes sense to use the less permeable/stronger barrier. Adding mulch, if you don't already have it, may make the situation more tolerable. I also suspect that the lesser permeability also keeps the soil moister longer in the dry season here, and even that hasn't been a problem with the majority of the Calfornia natives in combination with succulents I used, as long as the watering isn't daily, (I typically time it for 2 to 3 times a week for 20 to 40 minutes a cycle for my cool maritime Mediterranean climate where it never gets all that hot, seldom above 75F in summer). |
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