Forums > Specific Focus > Home, Garden & Construction in Mexico

heathesq

Jan 25, 2005, 7:03 AM

Post #1 of 5 (2970 views)

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Sagging Patio Floor

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We have a large (80 square metres) patio that runs along the length of our house. The land slopes lengthwize, so the patio is built up with a sone wall/foundation. It is sagging more and more with many dips that collect water and emerging cracks between the tiles. Friends tell us this can spell trouble if not corrected - gradual colapse, cracks in the wall, etc.

Questioons:

1- does it need quick attention?
2- what options do we have?
3- can I simply seal the cracks or will I have to retile?

Don

Jan 25, 2005, 7:30 AM

Post #2 of 5 (2962 views)

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Re: [heathesq] Sagging Patio Floor

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You should hire an engineer to look at the patio and make a recommendation. Hard to give repair advise over the forum without seeing the problem.

Esteban

Jan 25, 2005, 8:33 AM

Post #3 of 5 (2953 views)

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Re: [heathesq] Sagging Patio Floor

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Don is correct. It's hard to determine the problem with your description. I'd guess a few possibilities but that's about all it would be.

1. Below the patio, the base wasn't compacted correctly and has settled over time.
2. The base could be eroding/settling from some kind of water intrusion ie drain water, leaky pipes or agua negra leaks.

Please let us know what you find.

heathesq

Jan 28, 2005, 10:23 AM

Post #4 of 5 (2913 views)

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Re: [heathesq] Sagging Patio Floor- update

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Well, you guys really make me think. Went into panic mode for a while until I concluded no problema.

Hear is why:

Patio has a drain and I suspected it might leak. Pluged hole, filled it up. No fall in water level. OK
Left water alone for a couple of hours and the meter did not move.
Planned to block sewer outlet and see if waste system was leaking, but found that sewer was just an outlet from a septic overflow which is burried somewhere and system has connector-collector-holes instead of y-junctions so that it would not back up neetly. Inconclusive.
all water stuff is on east side of building except for outlet pipe. The patio is on the west side. Problem unlikely.
No subsidence elsewhere, except that when we replaced tiles in lr/dr the floor had sagged. Like that, this sag is in the centre of the area. Conclusion - slow compaction.

Our budget tells us to fix this later. When we do I hope to simply tile over the existing floor with the addition of a slope,. not a drain. Still the sunken parts sould hollow to tapping, so it might be best to smash things where they sag and see how big a gap has developed. Tell you next year.

Thanks for the good advice

Esteban

Jan 28, 2005, 10:49 AM

Post #5 of 5 (2906 views)

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Re: [heathesq] Sagging Patio Floor- update

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Proper compaction is a problem in the USA too. Technically, you shouldn't put over 18" max of fill, without compacting with a vibrating compactor. Different soils require a variation on that theme and the water content of the soil has to be correct. In Mexico, sand is the best material for filling below patios because you can almost achieve good compaction by flooding the area with water and letting it dry out. In Mexico, proper compaction is in the very infancy of technology. Roadways, public underground infrastructure and a myriad of other situations require compaction tests at every "lift" (18" of fill). Compaction testing equipment appears to be available in Mexico equal to the availability of breathalyzers.

Heathesq: Your best bet is to cover your existing floor with a layer of concrete, reinforced with steel. Like you said, make it drain by slopping away from the house.