The pipe should be lower than the interior slab (maintenance/mud slab in your case) and placed on 4" of crushed stone then covered with crushed stone. The filter fabric should wrap the crushed stone from the bottom to the top.

To prevent silt from clogging the fabric a layer of sand can be added above it.

Here is a link that might be useful: Geotextile Filter Fabric

Its great to see people put effort and planning into the hidden qualities of building a home. You bring up valid points that are beyond the consideration of most builders, designers, and grading contractors. Ren's point is big one and often overlooked. The whole point of these details is to give the water a path of least resistance.

I think its a big mistake to omit filter fabric from gravel and pipe drainage systems. Youre right that the longevity and effectiveness depends on soil characteristics and how much water flow the site will experience is perhaps just as important. In theory, all drainage systems eventually clog.

I wouldnt overthink it too much especially based on your site description. We've built right on top of two swampy/ wet weather springs. We did PVC gravel burritos on both the exterior and interior. We also did stem walls filled with clean gravel instead of crawlspaces which was probably most important. If you do a crawl, slope the grade to a low point and consider a drain to daylight there.

Thanks for the posts. I posted a link below to a 2-page document that I think provides an authoritative guide to drainage and filtering.
For our application, layering clean gravel, woven filter fabric with 6%-10% total open area and a 4"-6" layer of sand, then well-draining soil should be "bomb-proof."
That may be "over-engineered," but we won't have to dig it up! OTOH, I feel sorry for all the folks who have one of the corrugated pipe and cheap fabric "sock."

Here is a link that might be useful: TenCateTechReport

I agree pconte. Corrugated PE with a sock, might perform well if its well placed and is at the bottom of a filter fabric protected trench of gravel. Gradient also helps. Certainly water flows faster and silt collects less in smooth inner wall pipes and you can snake it should it get clogged.

When the grading around the house is sloped sufficiently and downspouts are dropping six feet from the walls--or better yet, into their own drainage system--it's surprising how little water the weepers actually carry. The extra money spent on solid PVC would be more effectively spent on plastic membrane wrapping of the foundation walls.

The corrugated piping and "cheap" plastic sock works very well when used in conjunction with well-draining fill and a membrane/waterproofing. Will it be sufficient in a century or 300 years from now? I'll let you know then.

Re the post by "worthy" ...

I understand that a) keeping water away from the house, and b) preventing water from passing through the stem walls are the first line of defense.

However, I subscribe to advice posted in another thread that you cannot really plan an adequate drainage system without understand the context.

Our current 1929 home has a sub-height basement that was used for "hog fuel" and an old sawdust burner. I know from talking to an "old-timer" when I bought the house in the 1970's that it was built in the fill put in a natural swale.

Well, that swale is still draining -- underground -- from the back of my yard to the rear of the house. The walls have never leaked, but "springs" appear in the floor when Oregon rainy season sets in. Interestingly, the springs begin to flow in a sequence from the back wall of the basement to the front, reflecting the old swale's natural flow.

We excavated the back and put in a rigid 4" drain (as well as separate gutter drains) running to a sump hole and submerged pump. We didn't do anything on the other three sides of the house; except that ALL of our gutters are now drained to the city storm sewer, which is in the front of our house, downstream in the swale.

Result: No springs in most years and a LOT of water pouring from the perf drain to the sump hole. (I can lift the cover and watch this.)

On really, really prolonged, hard rains, the springs may reappear. But now they start at the front wall of the basement and progress "upstream." This obviously reflects a subterranean flow that exceeds the capacity of the buried waterway downstream from the house.

Our problem could not have been solved without a drain, and that drain needs to actually maintain its capacity for decades.

For the Sunriver house, the issue is peak flow from rain and melting snow drifts. It would be too complicated, and not very reliable to try to fully map the underground flows on our level lot (and the water has to go somewhere). So ... for a little planning and a few bucks, we want to include a bomb-proof drain in addition to grading, gutter drains and sealing the wall.