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104 votes

Can I pour concrete over a PVC sewer pipe without damaging it?

Move the hole. You know its in a bad place. If you break the pipe with your flag pole you will curse your own stupidity and hate the flag pole and that is how bad things start. If you do get away ...
Willk's user avatar
  • 6,613
54 votes

Aluminum window screen as wire mesh be for strengthening concrete?

Aluminum is attacked by the alkali in concrete. The reaction gives off hydrogen gas. There is a research paper, Corrosion of Embedded Material Other Than Reinforcing Steel (PDF) published by the R&...
MTA's user avatar
  • 11.4k
51 votes

Knowing where to drill holes in steel plate?

Lay the steel plate on the concrete where you want it. Draw a line around it. Cut a piece of paper to the same size as the steel plate. Place it on the concrete in the same position as the marked ...
Mark's user avatar
  • 3,841
50 votes
Accepted

Make a hole deeper than the drill bit is long

A 1.5" hole (38mm) in concrete is beyond any conventional drill. You might get away drilling empty block, but not a foundation. I'd suggest renting a big rotary hammer drill driver for this job. ...
Criggie's user avatar
  • 10.7k
44 votes

Rotating a concrete slab?

Slab on grade is probably the kind of pour you are referring to. The problem is only partially one of lifting the slab, the other half is having the slab rest again on the grade. These kinds of ...
Edwin Buck's user avatar
  • 2,213
42 votes

Why use a tube for post footings instead of directly pouring concrete into the hole?

There are many different reasons. You can have it above ground. Code often requires 6" above ground before wood contacts the concrete. You can calculate the volume a lot easier. You don't waste ...
Fresh Codemonger's user avatar
40 votes

Asphalt or concrete, which job first?

I would have the driveway and sidewalk both removed at the same time so you're not removing one next to a finished product. Then have the sidewalk installed. After the forms are removed and the ...
JACK's user avatar
  • 82.1k
37 votes
Accepted

Is it normal to use a grinder to finish a new driveway?

That looks like a very poor finishing job to me. I've assisted on many driveways and never had to go back with a grinder. Finishing it wet is all it takes and leaves the desired surface that isn't ...
JACK's user avatar
  • 82.1k
36 votes
Accepted

Masonry bits dulling after 3-4 holes

The hammering action of the drill isn't activating So the bit is overheating due to friction. It is supposed to hammer the material you're drilling into dust then evacuate it, not rub it off through ...
bobflux's user avatar
  • 10.1k
36 votes
Accepted

Why should you add dry mix to water and not the other way round

Yes, there is a very good reason. If you add water to dry mix in the bottom of the container, you get a nearly impossible to incorporate glob of the dry mix at the bottom. On the other hand, if you ...
jwh20's user avatar
  • 23.4k
36 votes
Accepted

How should I remove a swimming pool from my back yard?

Where I live (NJ, USA) it's illegal to bury a pool. If the pool was filled with soil and hidden it's possible you would have recourse to get the person who did it to pay for remediation. Unlikely ...
jay613's user avatar
  • 40.4k
36 votes
Accepted

Aluminum window screen as wire mesh be for strengthening concrete?

I don't think so. Screen will almost act like a divider in the concrete. You won't get good aggregate pass-through. Even if you agitate the mix enough to get the loose cement through, you're ...
isherwood's user avatar
  • 140k
35 votes
Accepted

Can these concrete protrusions be removed without a grinder?

Your options are dust or chips. An angle grinder with a diamond wheel would make quick work of it, but you'd want a helper holding a good shop vac directly in the line of fire. Otherwise, a cold ...
isherwood's user avatar
  • 140k
34 votes
Accepted

How to determine if drill is suitable for concrete?

More important than the power rating is the type of hammer drill. This is a very useful link which explains the full difference between a 'Hammer Drill' and a 'Rotary Hammer'. The former achieves ...
SiHa's user avatar
  • 2,743
31 votes
Accepted

What happens to foam insulation board after you pour concrete slab?

By way of example, the pink Owens-Corning FOAMULAR 250 product and the blue DOW STYROFOAM Brand SM product rated for 25 and 30 psi compressive strength respectively. If weight is distributed and ...
Greg Hill's user avatar
  • 31.2k
31 votes
Accepted

What bit should I use to drill a two inch hole in a solid concrete wall?

Hire a core driller. Trust me and do it. You will regret doing this yourself and the cost will seem like nothing in comparison to your struggles with drilling a hole that size in solid concrete. ...
T Taylor's user avatar
  • 364
31 votes

Can I pour concrete over a PVC sewer pipe without damaging it?

Never, ever, mess with any pipe underground. No matter if it is any kind of plastic, steel, brass, copper, ceramic, concrete, whatever. No matter if it is used for sewer, water, gas, electricity, ...
fraxinus's user avatar
  • 3,199
30 votes

Light switch on concrete wall

The problem is, the last guy used a cover plate intended for flush mount boxes that are buried in drywall. Probably because they are mind-controlled into only shopping at big-box stores. You need a ...
Harper - Reinstate Monica's user avatar
27 votes

Is a roofing delivery truck likely to crack my driveway slab?

Unless your home is a 20 bedroom mansion I would simply tell them to keep that off your driveway period. You can't tell what load it will take because it depends how packed it still is, what ...
DMoore's user avatar
  • 49.2k
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
  • 140k
27 votes

Hole dug from underneath basement floor

The hole is from something that used to go through the concrete. Check it out. There is a circular concrete ring around that hole. Here is the original and I outlined ring in yellow. A thing ...
Willk's user avatar
  • 6,613
27 votes

ICF home -- are columns in the photos load bearing?

In a concrete wall (which is what an ICF house is built from) those are certainly load-bearing concrete columns. It would have required some very deliberate design to make the header over that space ...
Ecnerwal's user avatar
  • 220k
26 votes

Is it normal to use a grinder to finish a new driveway?

Jack has a good answer but want to add. This strikes me as a concrete job done after they did another with whatever was left over. If the mix is that dry there could be major long-term issues. ...
DMoore's user avatar
  • 49.2k
25 votes

Crack in concrete block garage wall

Yes, you should be concerned. Cracking like this is caused by movement (the structure has moved, such as settled) and this type of cracking is unusual. This needs to be reviewed in person by a ...
Ack's user avatar
  • 5,729
25 votes

Crack across front of garage floor

Good news, that is not a crack in your garage floor. It's just a damaged cosmetic connection from garage floor to the pawers. Someone already patched it before. Since those are thin, it will not ...
Traveler's user avatar
  • 17.9k
24 votes
Accepted

Is concrete dust from remodel dangerous?

My layperson's view: The link between silica dust and lung cancer exists primarily in industrial settings (mine, refinishing, construction). The people who grind down the concrete in their usual ...
P2000's user avatar
  • 16k
24 votes

Hole dug from underneath basement floor

Mongolian Death Worm Pour 13.7 oz of Diet Dr. Pepper into the hole to keep the worms away, remove the white glue and other foreign materials, and then patch normally. If necessary, fill the hole with ...
gnicko's user avatar
  • 5,615
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
  • 25.6k
23 votes

What is this concrete slab in my front yard?

Most likely access to a septic system, or sewer sump. Impossible to say for sure without gathering some hefty help and picking it off, or consulting old documents about your house. It covers something ...
Ecnerwal's user avatar
  • 220k
22 votes

Make a hole deeper than the drill bit is long

If you are using a core bit with a shaft for which there's an extension, you'd probably have thought of that already. As far as I know there's no extension available for SDS plus or SDS max shanks. ...
batsplatsterson's user avatar

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