32 votes
Accepted

How do I self-repair a section of crumbling basement wall, or should I hire a professional?

It looks like a cosmetic DIY patch-job was already attempted before. The current situation is exactly how you can expect your attempt to turn out. This is a structural issue and I would hire a ...
MonkeyZeus's user avatar
  • 16.5k
27 votes
Accepted

Why did cracks form over the rebar grid in my concrete footings?

This is known as "plastic settlement cracking", a type of shrinkage crack. It's the result of the rebar being too close to the surface. As water settles out of the concrete, it tends to ...
isherwood's user avatar
  • 135k
23 votes
Accepted

What to do with sprinkler pipe under spiral staircase foundation?

Dig the hole bigger. Buy four elbows, some pipe clamps and some extra pipe. Turn off the water for that pipe. Cut the pipe and with the elbows have it go around the box. Make your footing and no ...
crip659's user avatar
  • 23.7k
19 votes

Can a power transformer cause building vibration

You mention the vibration happens more often when it's cold. It could be related to the building's heating system or, perhaps, the outdoor unit of a HVAC system with an old or imbalanced fan.
Telescope2334's user avatar
18 votes

Can I pour a concrete foundation in multiple pieces?

Yes, you can do that. Provide plenty of rebar length past the joint. The vast majority of commercial projects are poured in sections, and virtually everything more than 60-70 years old was poured in ...
Ecnerwal's user avatar
  • 211k
18 votes
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Contrator made Concrete parallelogram for shed foundation

I am not going to get into payment/ legality/ recovery discussion. Obviously the guy messed up and you will have to deal with that as best you can. Removal and redoing the slab would certainly be ...
Kyle's user avatar
  • 4,533
15 votes
Accepted

In a house fire, how hot does the foundation have to get before it too has to be replaced?

The information is incorrect, the temperature at which concrete becomes unsafe for re-use is significantly lower, 570 degrees F actually. The 'telltale" sign is if concrete that was not charred from ...
JRaef's user avatar
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15 votes
Accepted

Does this water tunnel for rain look ok?

Without some sort of retention, that trench will likely cave in or mud up. Using the existing trench, you can improve it with a bit of effort: Dig the trench a bit deeper and lay some "big-o"...
P2000's user avatar
  • 15.8k
15 votes

What drill bit should I use to drill a 2-1/2" hole through 8" of concrete?

Core drill, preferably wet. Look into rental for the tool. If doing it with a dry bit, stop often to vacuum the dust out and allow the bit to cool. If you overheat diamond it either turns to charcoal ...
Ecnerwal's user avatar
  • 211k
15 votes

How can I seal a foundation vent?

I'd suggest that the problem is the flower bed, not the vent. Grade should be reduced and sloped properly to prevent the problem. Consider rain gutters in the area. You could also switch to a flower ...
isherwood's user avatar
  • 135k
14 votes
Accepted

Can I pour a concrete foundation in multiple pieces?

I agree with Ecnerwal, yes you can do that. I also agree to extend the rebar past the pour (drill holes in the form boards and extend the rebar out the holes). Code (and the CRSI) requires 30 bar ...
Lee Sam's user avatar
  • 3,768
14 votes

Does this water tunnel for rain look ok?

Call me old fashioned but there is a downspout which you can extend to your destination.
MonkeyZeus's user avatar
  • 16.5k
13 votes
Accepted

Can this water damage be explained by lack of gutters and grading issues?

You've really got a two-step question here Would a lack of gutters and grading explain the water? The simple answer is yes. That's the source here. Even without gutters and proper grading, should ...
Machavity's user avatar
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12 votes
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Can I run an underground wire to a shed on blocks?

Yes, the national electric code allows wiring in structures like your shed. If you plan on using UF wire for the run buried 24” deep you need to bring the wire up in conduit so the wire is protected. ...
Ed Beal's user avatar
  • 103k
12 votes

Why did cracks form over the rebar grid in my concrete footings?

Potentially there are three issues. The cracks could be caused by any single issue or any mix of the issues. Not enough clear cover over the rebar mat. The concrete mix contained too much water (...
r13's user avatar
  • 3,382
11 votes

Can I run an underground wire to a shed on blocks?

It is advisable to use a slip joint [expansion coupling] on the conduit stub up, otherwise nothing out of the ordinary. Around here, that's not out of the ordinary even with a poured foundation. ...
Ecnerwal's user avatar
  • 211k
10 votes
Accepted

What are my options for saving this building?

Ultimately, I decided to save it. I used stacks of cribbing with large beams to jack the building up off of the failing foundation walls. Similar to this (much larger) example: Once I had it up on ...
DonBoitnott's user avatar
10 votes
Accepted

Is it common for residential foundations from the 1960s to contain asbestos?

For concrete foundations no, asbestos is not an issue. However, the earth in your location may contain asbestos. In Northern California my brother is having a pool installed and they had to monitor ...
Ed Beal's user avatar
  • 103k
10 votes

Leaving basement forms on permanently

Sounds like a hack-job approach to me. That wall could be built from concrete blocks (aka CMUs or concrete masonry units), with bond-block rows and reinforcing steel, and grouted full, making it ...
Ecnerwal's user avatar
  • 211k
10 votes

How do I self-repair a section of crumbling basement wall, or should I hire a professional?

The first step of repairing a deteriorated wall is to knock loose and remove the bad materials to the solid base. However, in your case, I suspect there is nothing solid that remains, as the cracks ...
r13's user avatar
  • 3,382
10 votes

What to do with sprinkler pipe under spiral staircase foundation?

A pipe rupture beneath the foundation could cause soil subsidence that will destroy your staircase. For that reason I would now route the pipe far from the staircase. Cut it inside the hole you dug, ...
jay613's user avatar
  • 37.1k
10 votes
Accepted

What's the intended purpose for these rebar protrusions?

Those pieces of steel are not rebar, they are form ties that are used by the foundation people to rigidly hold the inner forms and outer forms at a fixed distance. They are held in place during form ...
MTA's user avatar
  • 11.2k
10 votes
Accepted

Joist are not properly attached to the band joist - found by home inspector. What does the repair entail?

Your rim board's purpose is to prevent the floor joist end from rotating. Imagine standing a couple of 2x12s on a flat surface with a sheet of plywood on top. Standing on this plywood the platform ...
popham's user avatar
  • 9,109
9 votes
Accepted

Should I repair or replace floor joists with holes in poor locations?

None of the holes are an issue. There is some slight compression with the one joist - in your top picture. But it doesn't look to be an issue and it is certainly not caused by that small hole. If ...
DMoore's user avatar
  • 48k
9 votes

Why are basement walls subject to tensile forces?

All walls experience tensile stress. This is not a force trying to pull the wall apart as such. The stress comes from lateral forces that can arise from two sources. Firstly, a simple lateral force ...
Chenmunka's user avatar
  • 1,286
9 votes

Concrete base for parcel box

Size will be an opinion mainly, but at least 5 to 8 cm(WxL) bigger than the box and about 8cm deep/thick. Anchor bolts should be easy to use to anchor the box and will make the box easy to remove for ...
crip659's user avatar
  • 23.7k
8 votes

Would rebar be necessary for ~3-4in of concrete used to raise a graded garage floor to existing slab height?

Frame Challenge: Instead of pouring concrete, self-lever, whatever, consider laying 2x4 pressure treated (or a plastic vapor barrier then non-treated 2x4) joists to raise the height. The 2x4s (3.5&...
FreeMan's user avatar
  • 47.1k
7 votes
Accepted

Will the concrete slab in a partially heated shed conduct a lot of heat to the unconditioned area?

I'd have no concerns about doing what you describe. I've seen it done many times here in frigid Minnesota. Build your walls (using treated lumber and suitable nails where it contacts the slab), ...
isherwood's user avatar
  • 135k
7 votes

Concrete base for parcel box

The depth depends on your regional frost line. For europe we have 80-150cm (varies wildly per source, depends on your location) frost line. That means, to avoid frost-heave, the textbook says the ...
Martin's user avatar
  • 3,064
7 votes
Accepted

Is this crack a sign of foundation problems?

Most houses move a bit. Unless you have some kind of sudden catastrophic fail, which is extremely rare, then really the trouble with foundation slippage or subsidence is it's usually so slow you can't ...
Tetsujin's user avatar
  • 11.4k

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