I'm getting ready to lay some blocks. Probably a lot of them, and quite a
few mixers full of cement. Some low decorative walls, walkways, pavers,
For block laying, should I buy a quantity of sand, lime, Portland, etc.? Or
should I just go with the premixed bags at the borg? There may be a slight
storage problem of unused materials from batch to batch.
Is premixed concrete with aggregate best for first coursing? How about cell
filling for grouting final wall?
What should I use for a stucco covering on it? Is that the same mortar mix,
or a special stucco mix?
What outdoor temps should block be laid at? And will it matter if the night
time temperature is below freezing? Down to about 20 deg. F.
I don't think there will be many complicated things about doing the type,
quality, or amount of block work I want to do. But suggestions are
I don't know why you think you'd need to buy lime separately.
Regardless if you're looking for cement or mortar-mix, it all comes in
one bag. Just add water, sand (and stone if you want concrete).
I'm not sure if you want to make mortar (for bricks/blocks) or concrete
- or both. I've never had the need to make mortar - if I did I'd just
as soon use the same portland cement I use to make concrete but just not
add any stone to the mix. Or I might do a little research to see if or
why real "mortar mix" is better than ordinary portland (type II) cement.
Are these regular construction blocks - concrete masonary units? 8" x
8" x 16" ?
I wouldn't think that you would want aggregate (stone) in your mortar
mix for application between blocks. Now, I don't know if you plan to
fill the space *inside* the blocks with concrete - if so then yes, we're
essentially talking now about concrete and not mortar.
Cell filling and grouting is two different things. I'm sure there are
books or on-line guides how to make a CMU block wall. I don't think
you're going to put aggregate in the grouting (mortar) mix. That would
just turn it into concrete. (to me, mortar or grouting is just cement
and sand. Concrete is cement, sand and stone.)
Lafarge makes something called "BlockSet" for this.
I think what you want is called parging mix.
I would never mix or place concrete / mortar below 40f, but that's just
me. The pro's that do this have blankets and heaters or otherwise make
sure the temperature of their projects don't fall below freezing (and
ideally don't fall below 35F).
Curing concrete / mortar when the ambient temp is within a few degrees
of freezing is just asking for trouble. It's critical to the hydration
process that the water component in the concrete / mortar not freeze
before it completes. This is less critical for mass concrete (ie -
driveway or some other massive amount of concrete) because it gives off
it's own heat of hydration. You won't get as much heat from grouting /
Totally nuts. Way too cold.
If you're going to mix your mortar / concrete and set your blocks when
the expected temps will go below freezing, then there's no point giving
you any other advice - the mortar will probably crumble and be very weak
after it sets.
The only other advice I'd give is to use clean, dry sand, and put it
through a filter to remove organic junk and small stones. Washed "brick
sand" is what you want. Dry and filtered.
I don't know why I think what I think, either. It befuddles me sometimes.
So, I'm just asking what I need and trying to describe it so that more
knowledgeable people can help me out.
As I tried to convey in the post, I will be doing some block, some walkways,
and other work. I will use bagged concrete for all concrete work, as well
as the footer.
Yes, except where not. (Half pieces for ends, etc.)
Now you ah getting, Grasshoppah! Mortar for the joints, concrete for
grouting the cells solid.
As mentioned before, want to fill with concrete, slightly less $$, I think.
For where I live, and the exposure, I want solid concrete fill.
WONDERFUL. SWMBO will not be pleased, but I now have a reason to put it off
until spring when she can help, and I can spend the winter finishing my
shop. Uninterrupted. TY, TY, TY!
I used to be a form setter. I hated it. But at least I learned that much.
Thanks for your help. I can get mustered this winter, and get it done this
spring. I want to set some forms for stairs, etc, and this will be nice to
just get it all ready to pour a little at a time. Maybe even call in the
big truck and have him make a big pour at the shop while we're spending
See these for more info:
I'm not sure what is usually done regarding filling in the cells. I
wouldn't think that it's common to fill in all the cells of all the
blocks. Some of these diagrams show rebar placed from top to bottom and
filled in with concrete - that's probably what I'd do.
I think a lot depends on if your wall is subject to lateral loading
(like a free-standing wall) with no right-angle bends in it, or if this
is soil retaining wall.
What I have seen done a lot on 6' high walls is spacing rebar about 4'
apart. Screens are put into the proper places within the mortar so that
grout does not flow out, and then the isolated vertical row of bricks is
poured so that there is a solid vertical with rebar every four feet. The
top course may be screened as well to seal the top course.
My wall will take a lot of freeze/thaw cycles, and we have blowing sand that
may keep the base wet all winter from the rain and snow. Therefore, I think
I'll just make it double strong with rebar and concrete so that I don't have
any big cracks. Also, it will be setting on blowsand, and tending to
settle, so horizontal rebar, even for a three to six course high decorative
pony wall. It's a whole lot easier than trying to straighten or jack up a
I've had good luck with both methods. I prefer buying 'mason's
mix'. The lime is already there. You add the sand. The
advantage of buying the mason's mix is you can go with an extra rich
mix for your stucco, later. [BTW-- don't try to mix it in your
cement mixer. Use a tub, or a mortar mixer on a 1/2" drill.]
Fine for filling cells. not sure what you mean by 'first
coursing'. Don't forget to shove some re-rod in those cells, too.
I make a stucco mix that has 1/2 the sand of my regular mortar mix in
the mason's 'portland.
I wouldn't want my mortar to go below freezing for 48 hours. A week
would make me happier.
Steve, you have multiple choices for mortar. Traditional is equal parts
Portland and lime to 5 parts sand, a bit easier would be to use
mortar/masonry cement and sand (the lime is already blended with the
Portland) available as type S or type N, or mortar mix which has the
Portland, lime, and sand already in the bag. All reinforcing cells both
horizontal and vertical should be done with real concrete - sand,
Portland, and gravel NOT masonry cement.
You might want to consider another method: dry stack the block, use
concrete to create the slushed cells, and use QuickWall for the bond and
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