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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Joists \ sleepers for decking over concrete patio

I'll be getting a 10x12 concrete patio attached to the back of my new house - not my first choice, but that's what it is. I wanna put Trex or some other composite decking over the concrete patio - ...
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Removing the concrete from the top off a concrete column

I have a number of 12" square concrete piers reinforced with 10 * 16mm rebars. The rebar extends to around 4m tall, while the concrete has been poured to a height of 3.3 metres. This an error because ...
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What can I do about a house with internal concrete floor with no DPM?

My partner and I have just bought our first home.A 1950's bungalow which is need of refurbishment. So far it has thrown us a ton of surprises! The worst so far being the floor in one of the bedrooms. ...
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Installing long 20ft metal poles in concrete around a football pitch

I work at a football club and I need to install some long 20 ft metal poles into the ground set in concrete. My question is how deep must the holes be and what diameter hole needs digging. The poles ...
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How to deal with soil erosion under slab floor of garage?

There is a small crack extending 10 feet down the center of the slab floor of my garage. The floor sounds hollow when I hit it with a 2x4. Also, there is a 4" water drain and I can feel air when I ...
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Can a slab under load be concrete jacked or otherwise supported without taking down the wall?

I have an issue with soil erosion below the front corner of my garage floor which has caused a crack to form and a piece of the slab (~4sq.ft) to sink. This in turn is affecting the portion of the ...
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38 views

Drywall skim coat over painted CMU?

I have a small section of wall (50sf) where the stairwell goes into the basement that is CMU (concrete masonry unit or concrete block) painted with at least an egg shell, possibly even semi-gloss. ...
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How should I prepare the site for a concrete step?

just bought a house where we've got an existing concrete slab porch that is 12" above the adjoining sidewalk and it does not have a step. We want to add in a large 6" tall x 3' wide x 11' long slab ...
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Self-leveling alternatives to gypsum concrete (Gyp-Crete, Pyrofill, Securock) over OSB?

Replacement options for < 1.5 inch pour? Details: Bathroom remodel (new tub, tile wall/floor, toilet, vanity). Old tile floor came up with finger pressure, found that the gypsum concrete ...
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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 ...
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What Cement Based Product Is Used for Smoothly Finished Floors?

I recently replaced a floor drain in my basement around which I had dug out the concrete, gravel and clay soil. When I sealed it back in, I laid down a bed of gravel and sand, and then used a ...
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Is it possible to paint concrete pavers

I have a large paved area that I would like to replace with lawn. My plan is to use some of the pavers as a border. They're plain concrete pavers (450x450mm) that look like this except about 20 years ...
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What product can I use to level an uneven garage floor?

I have an uneven garage floor that goes up to 1 inch deep from high to low level spots. I want to make the garage even. I was thinking of a self-leveling compound (watery). Which brand or type should ...
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113 views

filling in gaps in concrete patio

I have several 2" wide by 6' long spaces between the original patio slab and the newer slab that was poured after original construction of the house. The porch is covered so no moisture is getting ...
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3k views

How to patch concrete as invisibly as possibe?

I had a plumbing repair done this week that required them to jackhammer a small hole through a concrete porch in front of my house. It is small enough that I’ll probably attempt the patch myself, but ...
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How can I repair deteriorating concrete walls?

Our garage is about 80 years old and made of steel-reinforced concrete. The inspector deemed it structurally sound, but cosmetically the interior is a mess. The concrete has come loose (it is old ...
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42 views

How to drill to insert rebar into a large rock (5mx5mx5m)

I am pouring a reinforced concrete beam. It contains rebar. I would like to insert the rebar (horizontally) into this rock: What kind of drill and drill bit and to what depth should I drill to ...
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What is the difference between the coolness of different wall types in hot weather

Given a 30cmx30cm concrete beam and pier structure, with infill, and year-round (equatorial) daily temperatures of around 25C-33C, with around 80% humidity. What is the difference between these ...
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251 views

Can I repair the cracks between the bricks in my fireplace?

The bricks surrounding my fireplace have cracks between them. It's as if the thermal expansion/contraction has eroded the mortor between the bricks. I have had some serious fires in there and haven't ...
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Resurface exposed aggregate concrete patio

Is it possible to resurface an exposed aggregate concrete patio? My current patio surface is about 20 years old, and the aggregate has deteriorated a bit and is pretty ugly looking and painful to walk ...
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Concrete “post footings” for concrete patio floor?

The typical way of doing a concrete patio floor is to excavate soil at least 9", pour & compact gravel, then pour concrete. I was wondering, what will happen if: Excavate post holes, past the ...
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Stabilizing a gravel driveway with massive holes and steep inclination

I have inherited a 270 feet long driveway along a steep hill. It is part gravel/stone, and part concrete. It is in very bad condition. Every winter, rain threatens to wash away parts of it. Driving ...
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63 views

Latex paint over concrete primer

I have put concrete primer on my poured concrete walls in my basement. I have enough of construction latex paint primer to go over it all again. Is it okay to use on top of the concrete primer and ...
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43 views

What's the best ratio for sand-only concrete?

I'm making concrete countertops, so sand-only is the way to go to reduce voids in the forms. (I've done a half dozen samples). I've looked everywhere for mix ratios, but it's a weird request, and I ...
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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 ...
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How should I flatten (not level) a concrete subfloor?

In the final stages of finishing a room in our walk-out basement. This particular room has a long history, as it was originally a garage. Thus, it has a slight pitch from the back of the room ...
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Best way to support carport posts

I'm wondering if I can reinforce the posts in my carport as it seems one good earthquake could throw these off. Any thoughts on building a form out of wood and pouring concrete around and half-way up ...
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Should a post in a circular concrete form go through the bottom?

I am replacing a fence post that was in a circular 2-ft form. The old one had rotted where the concrete and post meet at the top - the next one will have the concrete above water level! But - I ...
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Can I sink existing concrete?

We got a house where it has a one foot strip of concrete that is 20 feet long besides a patio that is in good condition. On this 1'x20' strip there are two spots where the concrete has risen about ...
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37 views

Soil under slab (sidewalk) washed away and is now causing cracks down the middle

I have a 50' x 6' concrete slab in front of our basement that supports the same size wooden deck above with 6 post for the upstairs. The soil under it washed away due to poor drainage. I have fixed ...
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329 views

Best way to make a hole in concrete wall

So my house has concrete walls and ceilings. There a few places i would need to remove some large holes like for vents or light fixtures. I was looking at a concrete hole saw which seems to be a good ...
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Should I leave gap between my house's slab and a new one I'm laying outside in the garden?

I'm planning an outdoor kitchen. This will be a simple brick sided bench about 3 metres long and maybe 800 mm deep. I'm going to build it on a slab to support the weight and ensure a level surface. ...
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Will a few weeks of exposure to the weather damage cementboard?

I am getting ready to put Durock on my outdoor grill area. I am wrapping it with stone but it will be a few weeks before the stone comes in. Will the rain damage the cement board in any way or should ...
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Concrete stairs substrate preparation and layering

I need to pour small stair entry into my basement, about 4 steps and it is narrow, with a brick retention wall on both sides. I was going to first evenly grade and pack the dirt, then put gravel, ...
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164 views

Where to seam concrete countertop?

I'm looking to do a concrete countertop and would like some advice on where to make the seams.I was thinking either where the red or the yellow lines are. Thanks, greg
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Need advice on deck posts that will have concrete poured around them

I have a raised deck, attached to the side of my house on one side and held up by three posts on the other. Under each post is a small cement pad and the posts bracketed to those with a buffer piece ...
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What type of beam should be used over a split arch doorway?

I am building a building in Indonesia. It's using RC-frame construction. My builders don't have much expertise, nor do I. The basis for my building is three reinforced concrete pillars, 30cm * 30cm, ...
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How to increase height of existing concrete slab?

An existing patio has flag stones set over a concrete slab. If you were to remove the flag stones and thinset, what would be the best way to raise the level of the existing slab to make up for the ...
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239 views

How wide does a 6x6 concrete post footing need to be using an elevated post base anchor?

I'm building a pergola over a paver patio. The pergola will dimension 11'x 11.5' on center of post with 6x6 posts (4 posts), tied together with sandwiched 2x12 beams. I've laid out footer locations ...
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Are hairline cracks in basement concrete floor a problem - no water coming in

I notice quite a few hairline crack in my basement concrete floor. I've lived here for 14 years and no water has come up through the cracks. The townhouse was built in 1999 (so it is not a new pour). ...
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32 views

Are smaller or larger pavers better for covering a concrete patio?

I have a large ( 16' x 16' ) thick slab concrete patio that is pouted in 8 x 8 blocks. it has significant spalling and some settling. The concrete is 6" thick and situation in such a way that tearing ...
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laying a new bathroom sub-floor on to sand bed

The floor is fully ripped out and sand exposed. New plumbing ( wastes) in place but now to pour the new sub-floor. What do we do now? Approx. 0.5m3 for 100mm thickness.
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Damp concrete floor in bedroom

Had water overflow into bedroom and closet. New laminate floor removed. Concrete floor has glue strips from another flooring that is sticky in some places. Will thoroughly clean with as little water ...
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What to Look for in Professional Products for Vapor Sealing Concrete Slab

I'm planning to seal a concrete basement floor soon. While I haven't had any water problems, the basement has a smell to it which seems to be the smell of the soil/clay underneath the house. What's ...
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1answer
32 views

Can I build a car-port on the side of my garage?

I have a 2-car attached garage but three cars in the household. While I'm obviously aware I can just leave the third car in the driveway, it inconveniently blocks the cars in the garage and in the ...
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Ground preparation for deck pier block

I am planning to extend my deck, which uses pier blocks as below photo I cannot tell what's underneath this pier block because it was just dirt. There was no pour concrete for certain. So my ...
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How to level out or grind down concrete basement floor?

I had a french drain installed in my basement and the top of its cement sits around 1/8" to 1/4" of an inch higher then the rest of my basement floor. I need to somehow level this out so I can put ...
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Should cement be placed under concrete slabs for driveways or is sand enough?

I am about to get my driveway full slabbed using normal concrete slabs like below (i will be using rectangle slabs as opposed to square). The builders that came to give me an estimate said it would ...
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What is the proper way to prevent water infiltration between exterior stairs and wall

My house has a full flight of poured concrete stairs (covered with decorative stone) that runs parallel to (and butts up against) an exterior wall. The interior wall had water stains at the ...
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Easiest way to replace mortar around door?

I have a stone house and some of the mortar around one of my door frames has completely eroded away, there are big gaps and I can now see the screws that once screwed into the mortar too hold the door ...