Tag Info

Hot answers tagged

17

tldr; Stick to the recommended mix. Also read and up-vote woodchips' most excellent answer. Now, here comes the science: Concrete, mortar and grouts are all mixtures of Portland cement, water, and aggregates ( sand, and in the case of concrete: gravel.) Concrete is used for structural purposes, and it's primary role is to support a load. The ideal ...


17

My only guess is that a watery mix will have the layers settle in their different sedimentary layers with the fine cement settling to the bottom... One reason is that the aggregate can settle to the bottom much too easily, yes. This is called segregation and results in non-cohesiveness of concrete. Another reason too much water is bad is that it can ...


15

Codes and other guides provide nominal mix combinations that perform fairly in general conditions. In general, a 1:2 mix will give better strength than a 1:3 mix. But it is quite possible that a 1:0.5 mix might perform worse. Strength comes from inter-particle force transfer between sand grains and also from shear resistance provided by cement acting as ...


11

I wouldn't be too concerned unless there's mortar that is raised above the level of the grout - which you've already said there isn't. Scraping the higher sections to give a reasonable depth of grout would be as far as I'd go. A lot of adhesives these days are sold as tile cement and grout, though they do tend to be coarser than "pure" grout, so they are ...


11

Color This is the easy one. If you're going to use dark grout, you can use grey thin-set. If your grout is a light color, or you're installing glass tile or a porous stone, use white thin-set. If you use grey thin-set with light grout, glass, or porous stone, the color may show through. To modify, or not to modify In most cases, you'll want to use some ...


11

The white powdery substance is called efflorescence. It's bascially mineral salts leaching out of the masonry. The efflorescence itself may not be anything more than a cosmetic problem, however the appearance of efflorescence indicates that there's moisture present in the masonry. This is not entirely surprising--you're talking about an old brick wall ...


10

There are several things to consider. Unsanded grout (used with 1/8" tile spacing and less) is not as strong as the more commonly used sanded grouts. Given that fact, and the fact that the joints are narrower (making the grout more difficult to force into the joints), it going to more important to have the joints as free of excess mortar as possible. ...


9

If the mortar is crumbling and flaking, it MUST be removed. It is a tedious job, bit to assure a good solid surface, you have to remove all loose mortar, key it, and point all the joints. Let it cure a few weeks, be absolutely it is dried, then go for the finish. If you don't get to a solid base, you will be wasting your time and paint. Remember, the right ...


8

The reason is because of the hydration chemistry that takes place in the cement while it cures. When cement cures, it doesn't really "dry", the way a towel dries, but instead it reacts, the water ceases to be water and merges with the substances in the cement to form new molecules. Having too much will disturb the chemical interactions taking place and will ...


7

Is it the bottom row of bricks, and are they regularly spaced? (I guess that's only possible if your foundation comes up 40cm.) Because if that's the case, they're weep holes, and shouldn't be filled in. Otherwise, I'd go with @Tester101's answer.


7

Make sure you clean the joint very well (with a stiff bristle brush) making sure you remove all dust and debris from the crack. Mix up some mortar and put it in something similar to a pastry bag (the thing bakers use to decorate with). A large Zip-Lock bag with a nipped corner should work. Squeeze the bag so the mortar fills the gap making sure the mortar ...


7

Not really. Drilling is an inherently noisy activity. There may be low noise drills, but the act of rubbing hardened steel against brick at high speed will make a lot of noise. Lower speeds will reduce the noise, but you will take longer to make the hole. Using the hammer action will increase the noise, so try and avoid that if possible. The best you can ...


7

If you do it your self (not endorsing, and see comment by The Evil Greebo) you could put a more secure plug in by using hydraulic cement. To ensure that it does not come out, holes or cracks are usually back cut (the hole is made wider below the opening so that its diameter is greater than the diameter of the opening). This can be done with a small masonry ...


6

What is mortar doing on the roof???? you mean brick siding up to the roof or on the chimney? Regardless, adding mortar dye will not weaken the mortar if used properly. I would bet a paycheck that the contractor forgot to add it and is covering his butt. A good contractor would have discussed any concerns with the customer before doing the work. To use a ...


6

It's all about particle size, which is classified using the Wentworth scale or The Krumbein phi (φ) scale. Sharp Sand Sharp Sand, also known as Concrete Sand is a coarse sand with larger particles. This type of sand is typically used in concrete. φ scale - 1 to 0 Size range - 1/2 to 1 mm (0.020–0.039 in) Builder's Sand Builder's Sand, also known as ...


5

I'd opt for a fire resistant silicone sealant such as this one >> http://www.bostik.co.uk/construction/product/bostik/Fireseal-Silicone-Joint-Sealant/340 That's from a UK site, but I'm sure there are similar products in your part of the world. When it comes to cement then flexibility is usually imparted by including lime in the mortar - although that's a ...


5

I have been working on my field stone basement as well (170 years old), and here is what I have learned: Having hired an actual stone mason (that's right; they still exist) to repair an area of wall that was very decrepit I learned some things that are helping me now, and I have also learned that some of what he was doing was not necessary. I have begun my ...


5

This is the same question you asked a couple of days ago. BTW, NEVER use silicone caulk on chimney masonry cracks, especially if the crack passes through. There are special masonry high temp caulks for this purpose. In your case where water is passing completely through the brick joints, you really need to have it repointed. Any competent contractor would ...


5

Technically your only option is to replace an impact drill with a pneumatic hammer - the latter drills much faster (so you produce noise for shorter periods) and the noise is different - lower frequencies (IMO less annoying). Also how you drill matters. If you need to make a series of holes you better make them in long series with short pauses instead of ...


5

With only 15lbs, two screws (one on each side) ought to do just fine. Just drill into the mortar with a hammer drill and an appropriately sized bit, then use either a sleeve type anchor with the screws, or you could just use a couple tapcon type screws as well.


5

What you're looking for is called an integral color and is typically done with pigments. Here is a source that I've used for other projects: http://www.directcolors.com/concretepigment/


5

I agree with shirlock homes. It will not weaken it if used properly. As for what to do now. You can dye it. There are acid stains and water-based dyes. It seems like acid stain would work better, but it is much harder to make it go where you want it. It is so thin that it just spreads everywhere. Painters tape just soaks it up. The water based stain ...


5

A few more point to think about: If mortar is too hard, it will not flex and therefore will tend to crack more so separate from the bricks. If the mortar is harder than the brick, then the mortar will wear down slower than the brick in rain/wind, other along timer with will leave the mortar sticking out that then collects water and weakens the bricks. ...


5

Next time, tamp the cement into the corners (using a putty knife, large screwdriver, gloved finger, etc.) after a couple inches is set down. If you wait until the form is almost full, it forms stronger bubbles and they are harder to coax out. Structurally, the curb is more than strong enough unless you anticipate automobiles driving over it. The major ...


4

I've seen powder concrete colorant on home improvement shows but to be honest I've never used it. The shows I've seen have had great results with it. Looks like you just throw it over wet concrete and let it soak in.


4

It is not so much about mortar as it is about the working process. You should clean out the old crumbling mortar to make place for the new one. Remove the old mortar so that all parts are firm and nothing is crumbling - you can even scratch out a bit of the old mortar. The very important part is to wash the wall properly with water so that all parts hold ...


4

Figure 5 shows the effect of porosity caused by excess water. http://matse1.matse.illinois.edu/concrete/prin.html I recommend reading the entire article. "The strength of concrete is very much dependent upon the hydration reaction just discussed. Water plays a critical role, particularly the amount used. The strength of concrete increases when less ...


3

Filling cracks in mortar with silicone sealant won't last very long. It might last longer than 6 months but I wouldn't expect it to last a 2nd winter. You need to get the brickwork properly repointed. It sounds like they're after charging you twice - once for the caulking and then again for the proper job, for which they will probably charge top price. ...



Only top voted, non community-wiki answers of a minimum length are eligible