Hello,

and the answer is "YES"

Certain installation require the fabric. Some instances are wet, spongy soils, sandy soils, and sometimes very heavy traffic areas.

The fabric will help to keep the patio from settling over time. I just got a client who wants me to do a patio/drive at here shore house in New jersey, and I am going to quote it with fabric. The soil is very sandy and the fabric is a must....

I'm not a engineer and can't give you specifics, but I can say that if they call for it then use it. I'm sure stone or paul can give you some more run down on the fabric also.

steveair

 

The fabric helps to create a stable base for your patio by helping to distribute the load evenly and keeping the base from sinking into the sub-base. We have clay soil here and the gravel will sink into the clay over time. The fabric should be a woven geo-textile made for this purpose--not weed barrier fabric.

 

Steveair,
You are wise to use fabric at the shore, everything there settles. I did a driveway at my inlaws place at the shore. I spoke to as friend that does work at the shore all the time before I did the install, he recommended adding at least 3 inches more base then normal and compacting the base with a vibratory roller instead of the usual plate compactor. I followed his advice and have not seen any heaving or settling in 4 years even after this was emersed in 12 inches of water during huricane floyd( the water sat on it for 3 days before finally draining away. just my 2 cents.

 

I'm going to emphasize some of lanelle's words about type of fabric. It should never be a weed barrier fabric. They are weak, and can hold water up in your base rather than allow it to pass.

Take a new piece of typar and form it into a cup. Pour water into it. See how long it takes for water to pass through.

Paul had made mention several months ago about a spun-bound geotextile. I don't know anything about that one in particular; in general spun bound is out. You want to use woven.

 

Thanks for the advice. I guess I'll use it this time. I never used it before and never had a problem but I guess it's better to be safe than sorry.

 

SteveAir, Lanelle, Paul, Stonehenge -

I know you guys are the experts so heres one I was wondering about. How far past your project do you usually go with your grid? I figure 3' or so, but I don't know. Just wondering! Thanks guys!

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<a href="http://communities.msn.com/guidosequipmentpics/">"Guido"</a>
David M. Famiglietti

 

Wow!

I'm an expert now..

thanks for the compliment, but I still got a lot to learn. Paul and stone got me by a mile here......but appreciated.

As for the fabric, heres what I figure.

If I get the install job at the shore, I think I am going to 'wrap' the fabric around a layer of base course.

what i mean is that, for the drive area for example, I'll probably go for about 9 inches of base, so what I will do is lay fabric, then lay 3 inches, compact, then lay 3 more, compact, and then 'wrap' the fabric onto the top of that course, and then finish off with the last 3 inches/compact. that way the fabric gets pinched around 6 inches of base. I think I'll wrap around 2 ft or so of the fabric around the side.

the reason I am doing it this way is from experiences at the airport. All of our runways/taxways are built on wetlands, so they are always sinking. When they do a repair, they cut out a section and use this technique for the base courses under the asphault. Now, its a little more in depth than what I suggested, but the engineers call for that 'wrapping' of the fabric also.

I'm gonna take another look now at exactly how they have it set, I think they even use another piece on top of the base course also.

steveair

 

Fabric, it's hard to determine if you need it or not from here but, general rule of thumb, when in doubt use it. Purpose of the fabric is to support the top layer of gravel and pavement from settling. Many things help define what type of fabric that you need, if you have a very sandy soil that won't compact well( shifts as you run the compactor over it) your fabric must go 2' to 3' past the edge ov pavement, if you have clay soils that are loose and not compactable then 1' past the edge of pavement is ok.
Woven vs. non-woven, this is hard to say you have to look at the spec. sheets for tear strength, punchure strength, permability, and diagonal tear strength, and match to job site. The more stone or large rocks that are on the site the higher the puncture strength you need, the mose loose matierial you have sand, loose clay, slitly soils the smaller the seeve you need.

One word is don't use landscape fabric it might be wide enough but it's not strong enough for this kind of work.

There are some spun fabric that will work, but they are very heavy(13 oz. per yd and up) most times a woven fabric is best for this type of work. Also make sure you get the widest fabric that you can so you have the fewest seams under your work, these are places where things can go wrong. We have a sticher that helps us eleminate the seams but still have had them fail under extrime conditions. Most times a double fold will help you elimnate the problems of seams with out buying a sticher.

Hope this helps some. if you have more questions or need help on this please ask.

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paul

 

Steveair - I can relate to your view from the runway repair because as you know, thats a big part of my job in the Air Force. We use geo-textile on "wet repairs" and use the same "tucking" method, but we use one layer under ballast rock and then another under the base course, but its the same principle.

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<a href="http://communities.msn.com/guidosequipmentpics/">"Guido"</a>
David M. Famiglietti

 

one more thing,

I guess reading the initial post, it sounds like the homeowner is suggesting it for maybe other reasons.

After hearing what is said here, maybe you (little green guy) should go back and ask why the client wants the fabric.

Could it be he thinks it will reduce weeds or something?

It won't, if thats the case. Just mentioning this, because I get homeowners who always think fabric under a patio will do this. The weeds grow in the the sand between the pavers, they don't germinate under them. I've often thought of sweeping in some granular pre-emerge with my sand upon installation sometimes, but figured it would not last very long.

A good idea now would be to go back to the homeowner, explain the situation and why the fabric may be needed, and then tell them that if the the site calls for it, then you will use it. Also, if they want extra security, then use it also, but be sure to come up with the right pricing for the cost/installation of it.

 

I thought of this too little green guy,because I couldn't understand why the customer would be telling YOU to use a geo or other type of fabric. If they are, they must have done their homework. I imagined it was a weed block they were talking about, but I went with where the conversation went! If it is, explain to them what Steveair said about how the weeds grow in the cracks. Also I think Lanelle mentioned it, but I think the weedblock will slow down the drainage and cause a problem in the future.

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<a href="http://communities.msn.com/guidosequipmentpics/">"Guido"</a>
David M. Famiglietti

 

If you want still more information about patio bases, you can find several discussions on the topic by using the 'search' tool at the top of the page. I think that 'pavers' would be a good word to use for the search. Also has anyone used the polymeric sand or other stabilizer for joints? Seems that I read that it helps delay weed germination.

 

I think weed prevention is the reason the customers wanted it and I already told them it wouldn't prevent the weeds but it got me thinking mabey I should use the fabric for stuctuaral reasons anyway.

 

I think 'patio base' is the title for the discussion a few months ago that got a really good response.

As for me being an expert - I feel like there are more things I don't know than things I know. But this is a great place to learn from everyone.

And about the weed fabric - I recently sent a note to the editor of Better Homes and Gardens - they had an article about how to install a brick walk - besides the 16+ inches of base they thought was necessary, they also recommended a 'landscape fabric' partway down the depth of base. That could be why the Little Green Guy got asked about it.

 

If he just wants weed control under the patio
then just spray some bromacil/diuron or other
suitable soil sterillant.

Karl

 

My own personal rule of thumb: If the customer wants it put it in unless you know for sure it won't work. I wouldn't want someone coming back to me and saying a job failed because I didn't put the fabric or whatever they wanted in there. It is their money.