New answers tagged concrete
1
On our jobs, the concrete guys never got the concrete perfect. Since we were setting the bottom plates in non shrink mud, they did not have to and the "higher ups" allowed the concrete guys to do this. Never the less, after the walls were poured, we would drill the plates, countersink the area where the bolts were if needed, wetted the top of the ...
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Concrete that's "fixed" like this is sure to begin crumbling right after the contractor moves out of state. I'd be dissatisfied with this. As far as I'm concerned this is a breach of contract and is the contractor's responsibility, even as far as removing the entire thing and doing it over. That's out of scope for this site, though.
The only fix I'...
1
If you want it to be precisely level, you can use a transit level or laser level to set clamped concrete forms similar to the ones in your second photo to the correct height. If you can't rent or buy a $2000 daytime visible laser level, get a cheaper indoor one and use it at dawn or dusk. Mine is a non rotary that cost me $40 second hand and would be fine ...
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Just a gut feeling, but based on what I've seen that will hold a brick patio flat for a long time, two or three three inch lifts of packed crush under a 5" slab with 10mm rebar at 12-15" should be adequate. If you want something set on dirt to stay flat and the way you set it a long time, multiple layers of tightly packed gravel give a flat, long ...
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I'm not sure if you changed your picture, but it appears there are no existing bolts or studs to worry about. If that's the case, one option is to clean the existing holes, then use the same size hammer drill to deepen the holes so you have a good 3-4" of good clean hole. Then use anchoring epoxy to anchor fresh all thread rod in the holes. Once you ...
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Is it possible to hammer the bolts out on the backside of the concrete plate ? by use of a sledge hammer.
The you can just use new bolts in the same holes - maybe you have to use some 2-comp epoxy.
If not then drill the top 2 inches away - starting with 6 mm and then drill again with diameter like the. It will cost you a drill or two (metal and concrete ...
1
I don't think the intent should be to separate wood and concrete. I think that applies to encased wood such as in footings where concrete retains moisture for some time. Wood and concrete are used together all the time.
In your case its just wood on a flat surface but it doesn't really do much as it is a flat surface so water will sit there.
The plastic ...
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In my opinion it's easiest to just demo out the concrete patch and repour and set new anchor bolts. Least labor, best look, best structure. You could even consider adding some colorant to the new cement for a new look.
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Inspect the anchors a little more closely. If they're the drive-in wedge type similar to the RED HEAD brand shown here (photo credit to Grainger), and if the installation hole was drilled clear through the concrete, then you may be able to simply drive them down into the soil below with the help of a hammer and dowel (a piece of rebar, a long bolt, etc). ...
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If you wanted to keep the post centered in it's current location, you could rotate the post 45 degrees and re-drill in place. You might not even need to do anything to the old bolts, as it's unlikely to be a tripping hazard so close to the post.
You'd probably have to add a plywood mount at the top to rotate the mailbox back to perpendicular to the street, ...
5
One thing that might work well is to get some hard rapid-set mortar (they make them in smaller packages for patch jobs like this). The old bolts can be drilled out of their holes (use a metal-drilling the diameter of the shaft), then you can get a new mailbox and concrete the holes before adding new bolts.
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The concrete looks intact enough for re-use, I can't see if the anchor bolts are good or not, if they can't be reused getting old anchors out of concrete can be tricky: you might have to move your letter box one inch to the side so that new anchors can be drilled into virgin concrete.
If you do move it don't leave the old anchors protruding they are a trip ...
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Typical pre-cast pavers are about 2" thick, so that's a reasonable experiential datapoint. I've got a few of those in the 16" square size that have been through 11 winters without cracking in a pretty serious winter area.
You can get fibers to mix into your concrete to help reenforce it - 2" is too thin for using steel reenforcement. Ensuring ...
5
Sealants are often used to reduce the maintenance requirement for fresh concrete (by municipal crews, for example). They're imperfect, though, so in hot, dry weather the curing concrete can still suffer moisture deficiency.
For that reason, regular misting is a marginally more reliable approach (assuming you're available to do so). It's also easier (no ...
8
All of those methods do the same thing.
The sealant method is done one time, no additional sealant needed.
The water spray method needs to be done regularly, maybe every hour or so. The dam method has time involved for making the dam, but does not need to be maintained as much as water spray.
All these methods are done only after the last troweling is done ...
0
You might have to use one of these drop-in anchors with an embed sucket. Enlarge the existing hole, if it is smaller than the sucket, and install the sucket with recommended adhesive. If the existing hole is larger than the sucket, clean the hole and fill it with mortar paste and the sucket. Do not install the curtain rod holder until the adhesive/mortar has ...
1
More cement and less water make the concrete stronger ; But major strength comes from steel rebar and aggregate. "Six bag mix" is the standard for good concrete ( 6 cement bags to a yard of concrete mix ). These may all be moot points ; cement is not an adhesive - it does not "stick" to the previous day pour. As described , between each ...
3
Adding excess Portland cement will cause the concrete to shrink more and accelerate the hardening process making it even more brittle than it normally is.
My Dad used to always say there are 2 types of concrete. The kind that had cracks and the kind that will.
Cement really has no strength because it is brittle add something like sand and rock for it to bind ...
1
Another option:
Self levelling low-spots only, and optionally adding plywood to smoothen the rest.
"self levelling" cement is not liquid as you think and you can apply it in patches without worrying that it will run like water. You have some troweling time to work low areas as large as say 5x5 ft.
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No, you can't resurface the surface economically, as it needs skill, and is a labor intensive business. You can repave, or adding topping concrete though. The original cement facing has simply flaked out due to weathering.
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The direction of drain should be from the house toward the end of patio. I'll consider to provide French drain along the retaining wall, then discharge to storm water system, or a sandy pit in your own yard.
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Tapcons and similar are available in stainless:
https://www.tapcon.com/products/concrete-screw-anchors/410-stainless-steel-tapcon
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You have various options. The thickness of the fastener matters. Really a hot dipped galvanized fastener of sufficient thickness should last decades. Are you close to a marine environment? - that will speed oxidation of fasteners.
If you want the fastener to never rust out you could go with stainless steel and epoxy. Something like HY-150 or there is a ...
0
I don't know how well it works but there are companies that will drill holes through the concrete and then inject a waterproofing agent under high pressure. This is normally done for walls but I'd guess could work for a ceiling. It might even work better as for a ceiling as it won't sink down the wall outside.
If you search for "concrete waterproofing ...
0
In the UK we get "Postmix or Postcrete" and it comes in a bag.
Dig hole to correct depth and width relevant to post size. Fill hole
approximately a third of depth with water and place post in hole. Pour
in postmix evenly around the post until no standing water is visible.
Position and level post as required. ... Do not mix postmix with water
by ...
1
I would get the best cutter that you can find. I have not read an ASTM rebar specification in many years , However , they were relatively tolerant . So they can be double stamped ; A mill can make all one grade which simplifies their operation . So they could make all Grade 75 and supply it for all lower grades because it easily meets the tensile ...
1
The International Residential Code (IRC) requires a minimum of 40,000 psi (Grade 40). (See ICC IRC R404.4.6.1)
I think most architects and engineers design for Grade 40 or 50, because they are readily available.
If your working in a high seismic zone or high wind area, they may use a higher grade. Also, commercial work is often Grade 80.
2
Buy a small electric cement mixer second-hand
The quality of mix is better than mixing by hand in a barrow, and of course is much faster. It'll also be useful for any other projects like paths, footings for walls, and so on. If you've got a large property, it's just generally worth having one.
You can buy new, and they're not too expensive. Cement mixers are ...
1
Concrete aggregate ( sand and gravel at correct ratio ) minus cement.
I get a dump truck load of that and then buy bags of portland cement. The ratio for mixing is 1 part cement, 5 parts navy jack. So one bag of cement will make 6 bags of concrete. Rent a 2 bag mixer and then barrow it to each hole.
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Delivery of ready-mix in a truck
This gets you a whole lot of mud fast. There are a couple of problems: First, the "short" (small) load fee may raise its cost by 50% compared to the per-yard price you were quoted. Second, they'll likely allow you something like 5-10 minutes per yard to unload the truck and may charge by the minute if you run over ...
5
Two yards is a short load in my area, and you pay extra for a short load. On top of that, you don’t have much truck time. By the time you add truck time for 73 stops, you will find the cost is well beyond your expectations.
I have a small hand mixer I use when I need a good mix in the hole.
At the farm we dump the sakrete and water in the hole and call it ...
1
You have to have your Footings completely clean. The only thing that is allowed to touch the bottom of a footing is a dobie. In-fact, if you have to be inspected, you will likely be handed a failed inspection tag for even slightly dirty footings, as clean footings are part of the checklist before you can pour in most areas, and furthermore; your piers will ...
0
The footing should be completely clean where the pier attaches to the footing. If clay or soil is left on the footing, the piers could settle when water enters the area and washes the dirt away.
Btw, the rebar needs 30 bar diameter to completely transfer the tension load. (1/2” bar x 30 = 15”) The bar will be in tension when the shed shifts sideways.
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The problem with just pouring a flat slab is the rock can migrate out if above grade. If this pad base will be at grade or below so the rock can not migrate it will be fine to leave it flat. If you are adding the rock on top of grade make it a monolith pour so the outside edge goes down to grade this also creates the footing I usually add.
If I think a ...
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To address the anchors shown in your picture, basically they're ordered from "cheap and useless" up to "pricey but actually holds". The basic wall plug, in my experience, pulls out so easily that even when they come included with things you're going to attach to a standard drywall wall, you're better off throwing them away and using a ...
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Square footings are checked for “vertical shear” (the force of a post being pushed through the footing) and “bending” ( the force that causes the footing to bow and break).
Thickening the footing AND adding rebar horizontally in the footing helps both vertical shear and bending.
The size of the footing depends on the soil bearing capacity resisting the ...
2
At a 3000psf bearing capacity of the soil underneath, each 8x8 post without footing can bear a paltry 27 sqft at 50psf live load.
(3000psf x 64 sq-in / 144 / 50psf) = 27 sqft
If this is all you need, you still have to worry about post tilt due to an uneven bearing capacity or hardness gradient under such a small post.
You need a soil analysis and a load ...
1
I saw a guy on youtube poor hot (almost boiling) water on the bucket and it released that way.
Didnt try it myself, but I plan to.
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We don't know how deep the wood goes - it could be an inch, could be 6". But dig down as far as you can. If it's shallow, then concrete will fill up to floor level, which, if you're lucky, will be the same both sides. If it's deeper, dig at least 3" out, and fill as before. If the levels aren't exactly the same, then compensate with more adhesive ...
1
Yes, that's exactly what you want to do. I've found that drilling holes, 1/2" since your wood is that thick, into the piece of wood can break it lose and make it easier to remove. Get as much out as possible and then fill in with your Quikrete.
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I would do the following:
support the roof - and jack it up a 1/2” extra to enable the new one to slide in.
drill and cement or epoxy the post support ( stainless is good) into place, these are usually adjustable so getting the roof level is possible.
measure the required length of post - from the support to the roof and the 1/2” can be accounted for in ...
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You have 3 main issues: 1) Hold your post and roof up, 2) Hold your post and roof down, and 3) Maintain a minimum of 6” distance from the post to the ground.
You need a steel connector with a mechanical anchor (bolt, etc.) to support and hold the post in position. There are several types of connectors that are suitable for retrofit applications...see below.
...
1
If the gravel is that thick it would need to be compacted to keep it from settling over time. It should be done in stages (lifts). Add a layer, tamp that then add a layer and tamp that until it reaches the height needed. An engineer provides this type of info regarding how much gravel at a time for each lift. I know this is not what you asked, but it is good ...
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Normally, you'd want to use any type of straight 2"x 8" planks. Why 8" instead of 6"? Because the 6" is really about 5.5" and if plans call for 6" slab, the 6" planks would be too small. You'll have to trench a little to get the planks down to 6" above grade. You'll want to get some rebar and drive it in every 3 ...
0
I’m no expert but it looks like you’ve made a good job for your shed base and will be more than substantial for a 6x4 shed. When you talk about ‘cement’ you mean concrete? So that’s cement with aggregate in for strength. If the wooden surround is level from side to side, once filled you’ll be able to strickle across to produce a smooth and level surface (or ...
1
The slab loading (pressure over area) is trivial - you have 4 square meters to carry 1600 kilos (rounding up) which is pretty much nothing for any grade of concrete.
The more important function is spreading that load (plus the mass of the slab itself) across the soil, but that's still a very low loading (roughly 4 KPa, plus the slab (at roughly another 1000 ...
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