Inspection of existing concrete homes in Mexico
Inspection of existing concrete homes in Mexico
(OP)
I am a pre-purchase home inspector about to start inspecting homes in Mexican resort towns, most of which are concrete, most of which apparently gets mixed in the street in from of the home being built.
I'm 30 years in residential/light commercial construction so I have something of a handle on concrete, but I'm open to any suggestions about how to inspect an existing concrete home.
1. How can I tell if beach sand has been used for finings?
2. How to spot excessive organic material in the mix?
3. How to spot mud that's been poured when it was too hot without the use of retarding agents. (what're the proper retarding agents?)
4. What else should I look for?
Thanks,
Kent
I'm 30 years in residential/light commercial construction so I have something of a handle on concrete, but I'm open to any suggestions about how to inspect an existing concrete home.
1. How can I tell if beach sand has been used for finings?
2. How to spot excessive organic material in the mix?
3. How to spot mud that's been poured when it was too hot without the use of retarding agents. (what're the proper retarding agents?)
4. What else should I look for?
Thanks,
Kent





RE: Inspection of existing concrete homes in Mexico
Beach sand - If on the Gulf coast, most sand is white thus I would expect to see with some rubbing of a wall fine grained, white sand if it was used. The pacific side is much more difficult since beach sand is more brown in color.
Organic material tends to be lightweight and in many cases will float to the top of the concrete causing pockets or pop-outs perhaps leaving some residue behind. Be on the look out for dark residual material in pockets.
Concrete poured during a hot day in a situation where it's mixed in front of the house with laborers and not truck mixed will have cold joints which may be discerned by color based on time set. Too much retarder and the concrete will appear to be very gray (greenish) in color for an extended period of time. It will be almost wet to the touch and much will rub loose relative to normal hardened concrete.
Other items to look for that cross my mind are lack of proper clearance on reinforcing - that is the reinforcing shows or the concrete cover is very thin in places.
Plumbness in walls and level in beams. Forms may not have been set/shored properly. Look for form blow-outs, areas where the forms bulged due to pressure of wet concrete.
Honeycombing of course - lack of good vibration/consolidation of concrete. It's not uncommon for concrete in those parts to go without or the usual substitute is to have laborers bang on the formwork with hammers.
I'm sure others will help out with additional concerns...
Regards,

Qshake
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RE: Inspection of existing concrete homes in Mexico
The items regarding aggregate can be tested using pertographic microscopic approach or chemical approach. You can test for chloride ions or other deleterious material using chemical means. I've used phenothalein for testing for chloride penetration for parking structures... might be a simple test for sea salt (I've never worked with this). Organics can be tested by weighing and oxidizing... Other than that, best approach is visual and a very strong qualifier that the review is visual only and that there may be latent defects not possible to determine using normal means...
Dik
RE: Inspection of existing concrete homes in Mexico
RE: Inspection of existing concrete homes in Mexico
RE: Inspection of existing concrete homes in Mexico
How about using a metal detector?
RE: Inspection of existing concrete homes in Mexico
RE: Inspection of existing concrete homes in Mexico
RE: Inspection of existing concrete homes in Mexico
RE: Inspection of existing concrete homes in Mexico
RE: Inspection of existing concrete homes in Mexico
RE: Inspection of existing concrete homes in Mexico
Section 3 of the ASHI standards deals with the structural system. Home inspection is basically a non-invasive visual examination and does not include structural engineering evaluation. This this is dealt with in Section 3.2. If you do not have a background in structural condition evaluation survey and structural design, consider teaming up with an engineer who does, and then offer this as part of your service.
I understand that US based home inspectors have been performing home inspections in mexican resort communities..and some have now even set up operation in mexico. Have you contacted any of them to discuss challenges etc?
RE: Inspection of existing concrete homes in Mexico
I'm 30 years in residential construction so I have a pretty good idea where and how to look for problems... and when to recommend an engineer. I've worked with a number over the years.
ASHI, NAHI and NACHI Standards are all pretty similar and while I haven't studied them all in detail, I think they were all written with protecting clients while limiting Inspector Liability in mind.
Yes it's non invasive and not technically exhaustive but I still use a moistue meter with probes (among other instruments) and also offer resistograph testing.
-Kent