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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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 ...
John's user avatar
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34 votes
5 answers
9k views

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

Our house had a nice cedar pergola in the backyard, about 20'x16', whose posts began to rot at the base. It was covered in grape vine... Nice for shade but not for a falling down pergola. Needless to ...
tbox's user avatar
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32 votes
8 answers
49k views

When 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 ...
Walter Stabosz's user avatar
28 votes
6 answers
8k 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. ...
Nicholas's user avatar
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24 votes
4 answers
11k views

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

I'm currently in the process of digging a hole in my front yard to install a flag pole. The dimensions of the hole are 16" deep and 24" in diameter. Once I reached my 16" depth, I ...
Randy's user avatar
  • 241
23 votes
5 answers
14k 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 ...
Blerg's user avatar
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22 votes
6 answers
17k views

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 ...
Agoor's user avatar
  • 231
22 votes
1 answer
34k 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 ...
viatheether's user avatar
21 votes
5 answers
28k 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, ...
Henrik VT's user avatar
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20 votes
2 answers
4k views

Asphalt or concrete, which job first?

I have an asphalt driveway with a concrete sidewalk meeting the edge of it. They both need to be replaced. Which job needs to happen first?
Carol's user avatar
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20 votes
1 answer
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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 ...
Kellenjb's user avatar
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19 votes
3 answers
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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 ...
Jeffyx's user avatar
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17 votes
7 answers
7k views

How should I refurbish a concrete slab with a rough surface?

I am about to commence work on extending my garage. I will be pouring a new concrete floor and trying to get as smooth a finish as I can. However, this will flow up to my existing garage floor which ...
James Drinkwater's user avatar
16 votes
3 answers
7k views

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

I am building a house and we just poured concrete 3 days ago and now it has some cracks, This is the footer with reinforcement : This is footer after pouring concrete : These are some cracks that we ...
Madian Malfi's user avatar
15 votes
5 answers
96k views

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 ...
Hightower's user avatar
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15 votes
2 answers
6k views

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 ...
Sjpson's user avatar
  • 167
14 votes
11 answers
6k views

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 ...
rbhat's user avatar
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14 votes
5 answers
21k views

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 ...
Tyler M's user avatar
  • 1,070
14 votes
7 answers
5k views

Light switch on concrete wall

My house came with a light switch installed on a concrete wall in the basement using a metal conduit, and a 1-gang metal box. Unfortunately, the light switch plate sticks out and it's easy to get ...
user142271's user avatar
13 votes
7 answers
6k 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 ...
Merkd's user avatar
  • 329
13 votes
10 answers
155k 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,...
Carl B's user avatar
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13 votes
9 answers
73k views

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?
Bryan's user avatar
  • 131
13 votes
3 answers
3k views

Crack across front of garage floor

I have a crack across the entire front of my garage floor. I believe that the crack was caused by a poor drainage issue that has been corrected. The drainage issue also caused the pavers in front of ...
Dean's user avatar
  • 161
13 votes
6 answers
24k views

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?
PriestVallon's user avatar
13 votes
4 answers
174k views

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?...
Randyaa's user avatar
  • 386
13 votes
2 answers
8k views

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 ...
Ruth Blanch's user avatar
13 votes
2 answers
6k views

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?
Larry's user avatar
  • 131
13 votes
6 answers
10k views

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 ...
matt wilkie's user avatar
13 votes
1 answer
40k views

Is it OK to install a concrete slab 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, ...
jerebear's user avatar
  • 233
12 votes
4 answers
11k views

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

What are the reasons for using something like Quikrete's Quik-tube for pouring footings for posts rather than just pouring directly into the ground with a galvanized anchor set into the top of the ...
g491's user avatar
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12 votes
11 answers
6k views

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 ...
Dan Mantyla's user avatar
12 votes
3 answers
62k views

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 ...
Ben Jackson's user avatar
11 votes
5 answers
2k views

Hole dug from underneath basement floor [closed]

Something has chewed or clawed its way through the basement floor. Our basement is underground obviously. What would be 5 or more feet underneath the ground and chew through a concrete floor? I found ...
Debbie Day's user avatar
11 votes
3 answers
5k views

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 ...
jnovacho's user avatar
  • 307
11 votes
6 answers
15k views

Can I pour a concrete foundation in multiple pieces?

I'm building a 25-meter (65 foot) block retaining wall. The engineering specifications require a concrete foundation for the block wall equal to about 4 cubic metres (141 cubic feet) of concrete, with ...
guest12345's user avatar
11 votes
9 answers
14k 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 ...
JohnFx's user avatar
  • 4,662
11 votes
2 answers
4k views

What is this concrete slab in my front yard?

House was built in 1964. Slab is about 3 feet across.
oilers128's user avatar
  • 369
11 votes
6 answers
2k views

Concrete base for parcel box

I need to build a concrete base for a mail parcel box on the ground. The parcel box is 36.6cm deep, 49.6cm wide and 112.3 cm high. It weighs about 15kg. What size should the concrete base be? How is ...
Mikki's user avatar
  • 145
11 votes
5 answers
32k 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?
Susan Buckner's user avatar
11 votes
3 answers
2k views

How do I go about repairing/redoing this uneven and damaged basement concrete floor?

I've got a section of my basement that I want to turn into a workshop, but one of the many things to improve is the floor. I want a smooth level floor for this section of the basement (I might ...
David Garrison's user avatar
11 votes
3 answers
84k views

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 ...
joshmax's user avatar
  • 546
11 votes
1 answer
4k 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, ...
Hounshell's user avatar
  • 295
11 votes
2 answers
39k 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 ...
jbg's user avatar
  • 339
10 votes
11 answers
50k 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 ...
iLikeDirt's user avatar
  • 12.6k
10 votes
3 answers
3k views

How to drill a hole into a thin concrete wall without breaking off pieces from the other side

We have thin concrete walls in our flat, ~7cm/2.7inch thick. I need to drill some 6.5cm/2.5inch deep holes with a diameter of either 10mm/0.4inch or 8mm/0.3inch (I prefer the wider but can live with ...
Kjara's user avatar
  • 395
10 votes
4 answers
4k 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 ...
Bill's user avatar
  • 345
10 votes
3 answers
15k 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?
Mike Steinhauer's user avatar
10 votes
10 answers
24k 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 ...
Nic the climber's user avatar
10 votes
2 answers
8k 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 ...
Mary Shelton's user avatar
10 votes
2 answers
2k 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 ...
BillDOe's user avatar
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