Concrete Concerns

[LinFox]

We are building a house on in the Mountain, actually a very very remote area with no electricty and it probably will never come through. The building is
22'7" square and 24 foot tall. We have the contractor going above and beyone when it comes to this building a sort of over kill which does NOT make the contractor very happy.

This is an all block building, we are putting rebar in the walls as well as durawall every course on the first floor and then every other course. As well as filling the blocks with concrete...

The footing was poured with 5000lb with fiber concrete and drains are being put in around the building. The first floor is a slab with 5000lb concrete. We will be putting in steel beams and such as well. Like I said over kill Im sure but its better to be safe than sorry.

My first set of questions are:

1. Any suggestions on other things we should do to ensure the building?
2. Are smooth end block stronger, not as strong, or the same as regular (not smoothed) block?

Thank you

 

[rimshot]

My first set of questions are:

1. Any suggestions on other things we should do to ensure the building?
2. Are smooth end block stronger, not as strong, or the same as regular (not smoothed) block?

Thank you

(Linfox)
============

First of all, you are truly building a bomb proof shelter. Why make any mason include durawall for every course? I Don't necessarily agree that dura wall in every course is helpful and may even take away from the workmanship and soundness of the wall. It is going to slow down the workmanship because technically the stuff is not supposed to just be laid on top of each course with mortar troweled on top but it is supposed to be pulled up so mortar completely surrounds it. If a concrete block wall fails it is strange but to me always seems to break at joint with durawall as opposed to courses w/o this supposed reinforcing.

I would further compare overuse of durawall with using a stronger grade of mortar like using "S" mortar over "type N". In many applications it is stronger but actually more brittle. In plain Engllish it might be overkill and detract from the actual durability of the structure.

Corner blocks are heavier than regular line blocks. Yes, they are probably even stronger because they are heavier because of a thicker corner web. But what is the sense of making your blocklayers have to work with something that is actually more dificult to work with. To me, the trade off takes away from the project in tems of workbility.

In the end however, you are signing the paycheck so the choice is yours. Just consider if the juice is worth the squeeze.

rimshot

 

[ray66v]

I will admit I am not a big fan of concrete blocks.

That being said, I am not sure filling the blocks with concrete is a good idea.

I would much rather have them filled with foam insulation, to cut down on the heat/cold transfer.

 

[biggerten]

First of all, you are truly building a bomb proof shelter.
rimshot

Bomb proof would require going underground.

This is a curious structure, I picture a young maiden (probably his daughter) locked up for her protection against suitors. But as I recall, she'll just let her hair grow, braid it, and lower it down for the eager young man guy to climb up to the waiting eager young woman. You can't fight Mother Nature.

 

[Pops15]

Most of the problems you see with older block buildings were caused by footings that failed. 5000# footings with fiber should hold up very well. Did you use rebar too? Why so much overkill for a house floor?
I agree with rimshot about the durawall. I also question filling the blocks with concrete. If you're going to do that why not just pour concrete walls? I understand your contractor's frustration. I certainly don't think you should cut corners, but I think you're throwing money at problems that don't exist.

 

[Egon]

What kind of foundation design did the foundation engineers come up.

Any slope stability issues with heavy rains?

Any flooding/washout possibility?

Does it meet earthquake/ high wind codes?

 

[rimshot]

<Bomb proof would require going underground.> (biggerten)
============================================

OK, if we are talking bunker busters and Linfox knows one is coming he better do more than just duck when he's inside his fortress (big smile).

I guess the point of all this is just what is needed and where to draw the line? Why wouldn't standard building workmanship and materiels handle the job? Maybe Linfox has a compelling reason for requiring any excess.

rimshot

 

[chucko]

if you are As well as filling the blocks with concrete. why not just pour the wall solid as that is what it will be anyhow?

 

[rimshot]

This point concerning block wall vs. Poured wall is a good one but actually needs some further discussion. If you go with a block wall and insist on filling all the cores that's fine but technically speaking it is not the same as having a poured wall.

You can lay up an eight foot high wall consisting of 8"X8"x16"blocks and then go ahead and fill all the cores but air locked areas will still be present. Why? Masons mud head joints and nearly all the mudded vertical joints seal up just another small air pocket. When you grout the cores this air pocket can not possibly be filled. Some will regard it as a weak spot compared with the grouted portions of the block. In almost all applications, block walls constructed with good workmanship are highly capable and sturdy for residential foundations. Poured walls are obviously even stronger but for most of us block walls have performed adequately. ymmv

rimshot

 

[LBrown59]

* I would never throw money into a house where elect wasn't available ?
If you ever want to sell it it will be worth next to nothing or worse yet you wont be able to unload it at all.

]*We are building a house on the Mountain, actually a very very remote area with no electricty and it probably will never come through. [/COLOR]
The building is 22'7" square and 24 foot tall. We have the contractor going above and beyone when it comes to this building a sort of over kill which does NOT make the contractor very happy.

This is an all block building, we are putting rebar in the walls as well as durawall every course on the first floor and then every other course. As well as filling the blocks with concrete...

The footing was poured with 5000lb with fiber concrete and drains are being put in around the building. The first floor is a slab with 5000lb concrete. We will be putting in steel beams and such as well. Like I said over kill Im sure but its better to be safe than sorry.

My first set of questions are:

1. Any suggestions on other things we should do to ensure the building?
2. Are smooth end block stronger, not as strong, or the same as regular (not smoothed) block?

Thank you

 

[EddieWalker]

There are allot of block buildings done all over the world that don't have anything in the voids. Just block on top of block. Some have stood for decades, others have isssues. In my opinion, most of the issues are because of poor soil preperation and/or the wrong design in the foundation.

When you say that you added fiber to the concrete, does that mean you didn't use rebar? Did you have an engineer design your footings? What type of soil are you working in and what is the depth that you have to dig down to avoid frost heave?

In my experience, dealing with homes and problems with walls, cracking sheetrock and trim, it's always the foundation that is causing it. What you do with the walls is secondary to what was done with the foundation.

Why are you using block walls? It's aweful hard to beat the strength of wood framing. Block cracks, transfers outside temps and is notorious for leaking when it cracks. The only time I'd think that block walls would be a good idea would be for a basement, or a wall that will be below grade. Even then, just the parts that are below grade would be block with wood building up the rest of the wall.

If it's for secruity, your entry points and windows are what they will be going through regardless of what the walls are made out of.

If it's to cover the walls in rock, wood with 3/4 plywood sheething and lathe over it would be stronger.

With all the added drawbacks of finishing it off, running your utilities and insulating it, I think block construction would also be more expensive.

If it's a fire issue, stucco is very effective. Fine Homebuilding had a great article about a house that survived the Firestorms in Los Angales when every other house was burned down to the foundations. This house looked like it hadn't even been in a fire, except for the landscaping was all gone. The owner had 4 pane glass, no roof vents of any kind and had doubled the thickness of the stucco, along with a tile roof. Basically, he made it fire proof, and it worked!!

Eddie

 

[Dargo]

Not knowing where the OP is, I assumed that he is building somewhere like in the USVI some other similar area. If the buildings are not poured, then block with core fill is the main construction. When going around with a contractor who specializes in building basements in areas with high water tables or where the basement drops into a flood zone, I was surprised to find that the engineers call for block walls over poured in place concrete walls.

In a freaking sloppy muck pit, for lack of a better description, I helped him lay 12 courses of 12" block walls on a 24" wide by 24" deep foundation that had 4 #8 runs of rebar on stands to keep them in place while the 5000 psi concrete was poured. For those who don't know, #8 rebar is 1" thick. Believe me, it sucked to use a manual tube bender to make the 90 degree bends to go in the corners. The 12" block walls were laid on that foundation and every other core was filled to the top with 5000 psi concrete with a stick of #8 rebar in each of those cores as well. At the bottom of each of the non-filled cores a weep hole was drilled into the bottom of the outside and appropriate tile and pea gravel was used to carry the water to the sump pump. He also used a huge amount of perforated pipe snaked under the basement floor, also covered in pea gravel, that emptied into the sump as well. That basically carried all water trying to reach the outside of the wall, water that got into the wall and water that got under the floor into the sump pump. Of course heavy mastic was used on the outside of the wall and the sump pump had a double redundant double deep cycle marine battery backup setup so it would still operate for days without power.

To my surprise, the guy who lives there has never even painted the inside of his basement walls and has never even had a wet spot on his basement walls, let alone any leak. Other homes in his area with poured walls always fight dampness and weeping walls. Obviously I'm not a hydrologist or basement engineer, but I learned quite a bit from the one guy who paid a top engineer who specialized in that sort of work to design his basement. This same engineer designs 'hurricane proof' homes for the islands. Due to the lack of the ability to get quality concrete and the expense, he has designed several homes that have block walls with poured cores and the like.

 

[tommu56]

The better way to fill walls is do it in lifts less than 2 ft if you want all the cores filled.
Bond beams in u shapped block you lay rebar in you and fill with concrete. Most buildings I have seen with bond beams and filled cores cores were filled on 4' centers and had bar in them too along with bar in the bond beams.

tom

 

[CurlyDave]

I have never seen a concrete contractor use a stinger to settle the concrete fill in a block wall.

I always do, and on a 6' wall get 4-5" of settling compared to just pumping concrete in. Then you add enough concrete to completely fill the wall.

 

[Hooked_on_HP]

When you fill blocks with concrete you pour the concrete pretty wet. I is hard to get stiff concrete in that small of a hole. also you usually use a chip mix insted of using 3/4 stone. When you put a vibrator in wet concrete all the rock settles to the bottom. I would also worry about the mortar crumbling from the vibrator.

 

[Pops15]

If it's a fire issue, stucco is very effective. Fine Homebuilding had a great article about a house that survived the Firestorms in Los Angales when every other house was burned down to the foundations. This house looked like it hadn't even been in a fire, except for the landscaping was all gone. The owner had 4 pane glass, no roof vents of any kind and had doubled the thickness of the stucco, along with a tile roof. Basically, he made it fire proof, and it worked!!

Eddie

I didn't see the article but that sounds like a house I saw on the news. The firefighters only had the resources and time to save one house. They did a quick survey of the neighborhood and decided the stucco house was the most likely to survive the fire so they concentrated their efforts on it. The home owner was all smiles when he returned to find his home intact.....he said he didn't have homeowners insurance!

 

[CurlyDave]

When you put a vibrator in wet concrete all the rock settles to the bottom. I would also worry about the mortar crumbling from the vibrator.

I am not very worried about the aggregate sinking to the bottom or the mortar crumbling in the 30 seconds or so it takes to settle the concrete fill.

I agree these would be issues if I used the vibrator for several minutes.