Questions tagged [concrete]

Concrete is composed of cement, aggregate (including crushed rock and sand) and water. In homes, it's frequently seen in the foundation, driveway, sidewalk, patio, and stone walls. Note that bricks use mortar in the joints, not concrete.

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34
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11answers
15k views

Is this cracking foundation under a jack post a problem that requires repair?

I am buying an already-built new home. I find this in the basement. The builder says it's okay, but I am really concerned. Is this really a big issue? What steps would be required to repair it? This ...
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7answers
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Pouring concrete, is it safe to add large rocks to increase volume?

Backround I'm going to pour some concrete to anchor a swing set. The base of the swing set that is being anchored is two 4x4s with a 2x4 footer crossed perpendicularly to the 4x4s. I have a bunch of ...
25
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6answers
4k views

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

Yesterday we had new concrete pads poured. We expected pour-day to be the last day. I saw them out there finishing, but when we went out that evening after everyone had left, it looked half done. ...
22
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5answers
11k views

Make a hole deeper than the drill bit is long

The longest drill bit I have is 23.62 inches and apparently the thickness of the concrete I need to penetrate is 27.5 inches. I don't wish to buy another drill bit, is there a smart solution? The ...
21
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1answer
31k views

Are cracks in a newly poured concrete basement floor a problem?

I'm having a new home built and found a large crack in the newly poured concrete basement floor and wanted to see if it's something I should be concerned about. The floor was poured sometime in the ...
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4answers
9k views

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

I am planning to install a 1.5-inch conduit through a poured concrete wall. I am planning on drilling a two-inch hole to accommodate the size of the conduit body. I have been searching up and down, ...
20
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6answers
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Contractor is installing a vinyl fence and posts but is not using any water with concrete. Is he doing it right?

I hired a reputable local company to install 6 foot vinyl fence around my yard. Salesman was telling me how they would be using cement to hold the post in place. To my surprise I see the workers use ...
19
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1answer
7k views

How to add on to a concrete patio?

I would like to add on to my existing concrete patio with more concrete. I will about double the size of the patio. My question is, should I have the new patio free floating from the existing or ...
18
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3answers
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What happens to foam insulation board after you pour concrete slab?

I plan on making a garage out of a large carport, and I've watched and I understood how to properly insulate a new concrete slab. 4 inches of gravel, vapor barrier, 2 inch foam board, 2 inches of sand ...
15
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5answers
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Why do builders say that wet concrete/mortar is not as strong?

I have been watching a few videos demonstrating the mixing of mortar and cement and a constant theme is that you must not have the mix too runny. I cannot fathom the reason... Does anyone care to ...
15
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2answers
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Crack in concrete block garage wall

I have a 2 story garage with the rear being cinder/concrete block walls. I just noticed this crack. Havnt lived here that long so not sure how long its been there Is this something to be concerned ...
14
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11answers
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Knowing where to drill holes in steel plate?

I have a concrete floor and I made two holes to bolt a 1/4"-thick steel plate. The problem is that the steel plates haven't been drilled yet. How can I determine where the holes will be drilled in ...
14
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5answers
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Masonry bits dulling after 3-4 holes

I'm using an 18v makita hammer drill with a 3/16" Bosch blue granite turbo concrete bit to drill 2" deep holes into concrete-filled cinder blocks. With a fresh bit, it takes about 15 seconds to drill ...
13
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7answers
5k views

Rotating a concrete slab?

Is it possible to use a hydraulic bottle jack or similar to rotate a 10 x 12' x 6" a few degrees or about 5 inches? I have a recent pour not quite in position. 3/8" rebar throughout in a 6 x ...
13
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10answers
133k views

Do I have to remove the old thinset before installing new tile?

I will be installing some new 12x12 tiles in two bathrooms approx 25 sq/ft each. When I pulled up the old tiles, there was no thin set that had made contact with them so the removal was very easy. Now,...
13
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9answers
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Should I set wood fence posts in quikrete with no supplemental water?

Setting wood fence post---I've heard to set wood fence posts using quikrete dry, allowing it get moisture from the ground. Is this a good idea?
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6answers
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Should gloves be worn when working with concrete to prevent it from coming in contact with skin?

I was told recently that concrete is slightly corrosive. Should gloves be worn when using concrete or is it fine to handle concrete as long as its not done on a regular basis?
13
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4answers
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How do you secure wood framing to a concrete basement floor?

I'm using Pressure treated lumber for the bottom plate in a basement finishing project. What should I use to seperate the wood from the concrete? What are ways to secure the bottom plate to the floor?...
13
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2answers
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Is a roofing delivery truck likely to crack my driveway slab?

I am having shingles delivered. The truck weighs 62,000 lbs, will this crack my concrete slab driveway? Also, they plan on a dump truck in the driveway to throw shingles from the roof. I am not sure ...
13
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2answers
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Can I build a concrete block wall over floor tile?

I am enclosing a tiled porch on concrete slab with a 3' short wall of concrete block, with windows above. Should concrete blocks be laid over a tile floor?
12
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11answers
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awkward driveway curve has cars nearly colliding with house, how to mitigate? [closed]

Bellow is an arial photo and a road-side photo of my new house. As you can see the driveway is an awkward curve especially when backing out of the car port to the side of the garage - you have to do ...
12
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3answers
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Driveway expansion joints are rotting wood: What to replace the wood?

My driveway was poured in sections with lengths of 2x4 which remained between the slabs as expansion joints. Due to heaving and moisture many of these are in poor shape. I replaced one once by ...
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3answers
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Why should you add dry mix to water and not the other way round

During renovation I have used all kinds of dry compounds, be it mortar, conrete mix, tile glue, grout, plastering mud, ... On every one of them the instructions say to add the dry mix to water and mix ...
11
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5answers
28k views

Can I mix latex paint into concrete

would like to color concrete mix can I use outdoor latex paint to mix in with the concrete?
11
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6answers
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re-using wood from a concrete form?

I strive to not waste materials wherever possible, and "use once then discard" methods are particularily irksome. So with this mind, what suggestions do you have for enabling re-use of lumber used for ...
11
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3answers
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How do I remove THIN layer of carpet glue from concrete?

The folks who owned this house before us were the cheapest people around. They glued carpet to our concrete floor with a very thin layer of glue. Now, I'm having a terrible time scraping it off. I ...
11
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1answer
3k views

How do I build a form and pour a concrete pad?

I have a new safe that I want to put out in the garage. I'd like for it to be in a specific corner, but that corner has a few quirks. First, the slab is pretensioned. No cutting, drilling, coring, ...
11
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1answer
15k views

Is it OK to pave without mixing?

Going upon the advice of a reputable builder, I used Quikrete fast-drying concrete for a small slab outside my house. Not load bearing. His recommendation was to dry-pour the whole thing. Framed, ...
10
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9answers
11k views

How can I pour a concrete pad with a circular hole in it?

Essentially, I'd like to put down a concrete pad for a patio, but leave a couple of circular areas within that patio unpaved (for planting shrubs). I'm familiar with the techniques for using ...
10
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4answers
2k views

Leaving basement forms on permanently

I am having an addition built on my home with ~600 square foot basement underneath. Because one of the basement foundation walls is very near (~1 foot) from the original home foundation, the concrete ...
10
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3answers
10k views

Why are there metal tabs protruding from my poured concrete foundation walls?

What are these metal things sticking out from my basement walls? Can they be removed? If so, how?
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2answers
3k views

Filling in a sunken living room to level of other floors

My sunken living room floor is concrete slab surrounded on two sides by higher concrete slabs at the level of the rest of the house. The other wall is a brick fireplace hearth. The wall opposite that ...
10
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1answer
917 views

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

Not long after the Oakland Hills fire in the early 90's I was talking with a homeowner. I ignorantly said that at least he can still rebuild on the same foundation. He said that at about 2,000°F the ...
10
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3answers
13k views

How do I fill in around waste pipes?

Broke the concrete in my basement to run new pipes for the basement bathroom. The plumber put sand under the pipes to support them at the correct angle. I asked him not to glue the vertical sections ...
10
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1answer
6k views

Foundation for structure on bedrock

We have the mixed blessing of a giant swath of exposed Canadian Shield on our property in Ontario. Literally a big flat area of exposed rock, no soil whatsoever. Scale is hard to see, but a ...
9
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7answers
2k views

Will old anchor holes in a concrete slab reduce its useful life?

An impaired driver jumped my curb and ripped my square mail post out of the sidewalk concrete that it was anchored into. The bolts were all ripped out of the concrete. Bolts went through the metal ...
9
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4answers
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Filling in 1/4" wide sharp joints on cured indoor concrete floor?

This concrete garage floor is 3 years old. It has these quarter-inch wide sharp joints cut in every 12 feet. All settlement/curing cracks are in the joints, but I don't understand why they were cut ...
9
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9answers
34k views

Why can't I drive this Tapcon into concrete?

I'm trying to drive a 2 1/2" long 3/16" diameter Tapcon into a 50 year-old concrete slab/subfloor to attach a new toilet flange. The instructions on the case of Tapcons said to drill a hole ...
9
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11answers
111k views

Would wrapping a wood fence post in plastic help protect it?

I'm geting ready to install a couple new wooden privacy fence gates on the sides of our house. One of my co-workers suggested to wrap the 4"x4" with plastic stretch wrap around the 2' part that will ...
9
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2answers
21k views

How can I level my basement floor, which has a 4-inch dip?

I googled today on how to level a basement floor. Most people recommend using SLC (self leveling concrete)... I don't think I can just use that because of the pitch of my floor (and from what I hear, ...
9
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8answers
20k views

Can I hang a heavy weight from a concrete ceiling if I reinforce it with fiberglass?

I'm investigating the possibility of hanging a pull-up bar/ rock-climbing training board from the concrete ceiling in my apartment. The slab is 180mm (7inches) thick and the (static) weight which I ...
9
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6answers
102k views

How much concrete for a fence post?

We're going to build up a 4' fence around our property sometime in here in the spring or summer with 4x4 posts. I've seen that you should bury 1/3 to 1/2 of the above ground post height; so this ...
9
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2answers
4k views

How can I get the 2-part epoxy smell out of concrete?

Six months ago or more, my friend used a 2-part epoxy (no longer have the packaging, but it's a double-syringe with clear liquids, purchased at Home Hardware) on something, and some of it (one or both ...
9
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3answers
5k views

Drilling holes in concrete

I'm not what you'd call a handy guy, and now wife wants me to put up curtains. This task is reduced primarily to getting a bit of metal stuck to the ceiling. I bought screws and anchors. The anchors ...
9
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3answers
83k views

How can I prepare uneven concrete basement floor for vinyl planks?

I have roughly 600 sq ft of basement that needs new flooring after some unfortunate flooding this past summer. We had carpet over concrete and are now looking to lay vinyl planks down. There is about ...
9
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2answers
33k views

Is it safe to drill small holes in load-bearing concrete beams for expansion bolts?

It seems to be very common to drill small holes in any kind of structural concrete for mounting fixtures without worrying too much about any kind of reduction in strength of the structure, but I ...
8
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2answers
2k views

How to determine if drill is suitable for concrete?

I've seen two drills - one 600W the other 700W. Both 0-3000 rpm. But for 600W some guy said it can't make it with concrete, while for 700W reviews say that it does it. Both are hammer drills. I'm not ...
8
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5answers
906 views

Best way to source concrete for a long fence project

I've done several small fence projects before, and hand-mixed concrete in a wheelbarrow for each post as I set them in place. However, I'm now looking to build a wood guardrail around a parking lot at ...
8
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4answers
350 views

1960s bomb shelter a safe place to wait out a tornado?

I have a 1960s 10x12x8 ft concrete room. It was built under our concrete kitchen floor which is at ground level in 1963. The concrete is 12" thick, except for the ceiling which would be about 24" ...
8
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1answer
1k views

What are these metal tags attached to my poured concrete basement wall?

What are these metal pieces attached to my basement poured concrete walls? They are about 2x2 with holes and were pressed into some kind of goop. These walls were poured in 1979. Can I remove them?

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