Replies

1. 
   Jeff_Clarke_ | May 29, 2001 09:27pm | #1

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   Don - Grouting solid is worth it, in my opinion.

   Jeff

1. 
   Adolph_Loos | May 29, 2001 09:45pm | #2

   *If it's a basement...definatly grout the cores and add reinforcing steel, as well. If it is just a crawl space... not much need to have solid block (it will not keep out water). The difference is in the type of load the block wall is subjected to. The higher the wall (the deeper the foundation), the more it wants to bend in due to the lateral load of earth/water. Usually, building departments have some guidelines on reinforcing basement walls.

1. 
   Steve_Hansen | May 30, 2001 12:20am | #3

   *Grout without steel (rebar) is almost wothless. It will have compression strenght but it will be unable to resist the stresses imposed by settling or expansive soil. Rebaring and grouting a vertical core every 2 or three feet will add significant strength. However, it does nothing to prevent inward bowing foundation walls or "step" cracks. There are two possible solutions. One is a reinforcing wire grid product called "sturdy wall" that is layed in the horizontal mortar joints between every third course. The other solution is to grout horizontal rebar in blocks that have a cut away for this purpose. All of these options complicate the block laying process and add cost.A block wall that has been properly reinforced with vertical and horizontal rebar (or sturdy wall) on schedule will be much stronger than a wall that has been completely grouted and almost as strong as a wall that has been reinforced and completely grouted.There is little to be gained by grouting an existing wall of any heigth. This is because you can not add the necessary horizontal reinforcements.The moral here is that if you want to reinforce a concrete block wall you need to plan for it in advance and incorporate it as you build.There are a couple of cost considerations. A properly reinforced block wall may cost more to construct than a formed, reinforced concrete wall. This is particularly true for basements. Depnding on what you are building, rebar and grout may buy performance that you do not need. This is wasted money. If your friend is not comfortable with the advice he is getting from his contractor he should ask around. I note, however, that most contractors are familiar with applicable codes and usual and customary building practices in your area. Grouting in rebar and filling cores only makes sense if conditions require it.

1. 
   Johnnie_Browne | May 30, 2001 02:40am | #4

   *I myself is building a block house which I planned on filling my cells. alhought the weight of the extra concrete will add weight to the footing. The extra cost of concrete and rebar is only adding $1500 to the total cost of the house. I,m adding rebar every four feet, #5 bar with open face lintel at top with two #5. The purpose of the block fill is for thermal mass and the fact this is hurricane alley.

1. 
   Chris_Koehn | May 30, 2001 07:36pm | #5

   *In this area we often install pilasters every 8 feet or so, filling the cores and re-barring. They are integral with the block wall. This works as a great lateral stiffener. I ussually call out dura-wall every few courses as well (probably the same as sturdy wall). The length of the wall, the amount buried (is it partially exposed) and the soil conditions all play a role here. I almost never backfill with native soils, unless I'm building on a glacial gravel pit. I pay the nickel to truck in #1 washed stone to backfill with. Does a lot to protect against moisture problems and frost heave. Talk to you excavator and see whose block walls have collapsed when backfilled and whose haven't- you'll be amazed at what an excavator can tell you about quality block work (and the lack thereof..)

2. 
   Don_Davies | May 30, 2001 07:36pm | #6

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   Friend is building a new house with block walls. I think that the walls should be filled, contractor says no. Filled walls should be much more solid, less susceptible to cracks, and would give him a good base to tie his framing to. Pros please comment.