concrete window sill cracked/deteriorated

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#1

Originally Posted By: srowe
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http://www.nachi.org/bbsystem/usrimages/more/Picture018-small.jpg ]


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#2

Originally Posted By: jpope
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Masonry units such as those pictured are quite porous. Moisture penetrates these blocks easily. Being close to the beach introduces moisture and salt to the reinforcing steel used in the construction.


Just a guess, but I'd say that most of those problems are associated with the salt air rusting the rebar. The rebar expands as it rusts and splits the blocks.

--
Jeff Pope
JPI Home Inspection Service
"At JPI, we'll help you look better"
(661) 212-0738

#3

Originally Posted By: jpeck
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Shawn,


That is spalling.

Water migrates in (along with the salt from the ocean) and rusts the steel in the concrete. When steel rusts, the surface expands (so I've been told) about 43 times in size. That is like ice damage, only it is caused by rusting steel, it pushes the concrete outward.

Once you see the cracks, there are only two options: 1) chip out the concrete, clean the steel if the steel is salvageable otherwise replace the steel - means chipping out even more concrete, patch with high strength concrete - typically it is pneumatically applied; 2) then you always have this option for everything, regardless of what it is - ignore it, but it just gets worse.

In the case of window sills, remove the windows, replace the sills, the re-install NEW windows (the old windows may no longer meet required wind loads) or at least check to see if the old windows do meet the wind codes (but once you've got the old, corroded, salt spray eaten window out, why on earth put it back in?).

Were you able to go in the crawlspace? I'd guess there was spalling on the inside too.

--
Jerry Peck
South Florida

#4

Originally Posted By: srowe
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Hey Jerry (and Jeff),


I knew it was spalling but being a home inspector and not a contractor I was more curious about a proper fix (and I think you answered it Jerry). This house may be just a tear down in a couple of years so I think the buyer is more interested what he do to make it last a few more years.

No---i did not enter crawl space. Actually, don't plan on doing the inspection due to conflict of interest.

#5

Originally Posted By: dedwards
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A similar topic is the use of “beach” sand for mortar joints. I’ve been told by some old timers that before the days of building codes and such it was common in coastal areas to use beach sand for the mortar mix. The mineral content is extremely high and the mortar joints literally start to fall apart. I have found a couple in some very old dwellings and you can rub the joints with a finger and it crumbles.

#6

Originally Posted By: jpeck
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Doug,


Back in the old days, they used unwashed beach sand for the concrete down here (we have plenty of beach sand). That was common practice in the 20s (the few concrete homes constructed back then) and in the 30s and early 40s.

By the late 30s and early 40s, they were washing it, but not well enough, still caused problems.

After sometime around the mid 40s (my best guess) they stopped using beach sand altogether.

And I'm not talking about just for mortar, for all concrete. Just for mortar would not be so bad.

--
Jerry Peck
South Florida

#7

Originally Posted By: dedwards
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Jerry,


Same thing up here in Pensacola area. Lots of houses here over 100 years old. Some real challenges at times. Folks watch a couple episodes of HGTV or This Old House and think they want to take on a “fixer upper”


Doug

#8

Originally Posted By: dbowers
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The best fix is to note the condition - then refer them to a competent masonry contractor for evaluation and repair. We are the screening process - not the final solution.