concrete block

[rongaudier]

After looking at many different options I am thinking of taking a radical departure from my original plan of building a wood-frame house on piers.

I did some number crunching, and it appears that a house built with concrete block walls on a slab may be significantly cheaper than any other form of construction I can find.

Here are the advantages:

1: Termite proof.
2: Fire proof.
3: Rot proof
4: Very wind and airborne missile resistant (when properly re-enforced and voids filled with concrete).
5: High thermal mass.
6: Excellent sound deadening properties.
7: I would have the ability to complete the project over a long period of time. This is important to me as I plan to do most of the work myself and travel frequently on my job. I don't want to be rushed in the construction process as I would with just about any other kind of construction.

Disadvantages:
1: Poor insulation properties. (I live in the deep South cooling is more an issue than heating).
2: Appearance. (This is subjective and can be remedied with various siding options which can be installed at some future date).
3: I'm finding a difficult time finding home plans for concrete block buildings.

I have a couple of questions for the group:

1: How difficult would it be to adapt a wood frame houseplan to use concrete block external walls?

2: I have a specific plan in mind www.houseplanguys.com plan 79-229

3: mjpliv, you have looked at this plan what do you think?

[Rich]

Block walls can be overlayed onto just about any plan. Thicken the walls and get details for the steel lintels for door and window openings. You'll probably need extension jambs for all your doors and windows also.
If you really want the best of the best for all the issues you set forth above - I would look at ICF (insulated concrete forms). It can be a do-it-yourself job with the input of the manufacturer.
Take a look at www.concrete-home.com (another website I moderate).

[rongaudier]

Thanks for your input. I have been looking into ICF's for some time and they do seem like the ultimate system. Unfortunately, the cost of an ICF project is just a bit too prohibitive for me right now. I believe the blocks alone cost about 8-10 USD per square foot, whereas it looks like the whole wall system using ordinary concrete block may run as little as $2.00 per foot for materials (maybe less)? Another advantage, as stated in my previous post, is that I can do the block wall a little at a time. The ICF project would have to more or less all be done at once. That's a big chunk of change to come up with at one time, and more of a project than I can do right now.


Have you heard of dry stacking? Where can I get more info on this system? It sounds really interesting. Stack the blocks without mortar and apply cement to the external surfaces of the blocks to hold it all together. Dosen't seem like it would work, but apparently it does. Makes wall constuction comparatively quick and easy. Also works with about any CMU.[/u]

[VOBB]

Ron,


Your comments about the numerous advantages of using concrete block are duly noted.

I would like to note that the disadvantages of:

1. "Poor Insulation" be taken in context compared to wood construction. Many people do think that CMU have a high "R' value. In fact, the 6" wide VOBB block have a R value of only .95 (less than "1"). However, we have found it very simple and cost effective to buy one-inch insulating board and attach it to the exterior walls. One man who lived in a 3100 sq. ft. VOBB home in LA compared his utility bill to his neighbor's bill who had only a 2800 sq. ft. home. The VOBB home owner saved $200 last month in July comapred to the smaller home. The cost for insulating board is about $1,500 (material only) - depending on the size of the home.


2. Appearance of a concrete block compared to a 2" x 4" are basically the same - "Ugly". For this reason sheet rock is put on the inside and brick, stucco, etc. is put on the outside of 2" x 4" wood. When people try to make block into a finished product, they will end up on the losing side. I suggest you plan to put on both the outside and the inside the same quality of finish as you would on a home built out of termite food and fire wood.


3. Home plans made for concrete block can be easily adapted. I looked at the home plan you designated as follows:

Floor plans for Southern house plan 79-229

The Southern style of home design features a hip roof, small window panes, pedimented doorways and transom lighting.

This set of plans should be a piece of cake to adapt to VOBB.

************************************************** *

Please look closely at the cost. It is your money and I suggest you not let anyone you misinformation.

For a quality VOBB wall which has no weak mortar joints, the material cost would be less than $3 per square foot. Yes, just the VOBB blocks themselves cost less than $2, but you need grout, rebar, etc.

Yes, the mortar joint is the weakest part of a "regular" CMU wall. At VOBB, we eliminate these weak mortar joints. According to one engineer witht he NCMA, a wall with rebar is about ten times stronger than a wal without grout and rebar.

We invite you to come check out a quality VOBB construction site.

Many of our VOBB projects were completed by people have never laid a concrete block before in their life as it is so simple.

Thanks and have a great day,
JG
Building better homes for our families, friends and neighbors
337-781-0705
www.vobb.com

[colonial carpentry]

The dry stacking sounds crazy and you will probably get many a raised eyebrow when you mention the idea to anyone.My neighbour built a log cabin on a dry stack system.I would seriously consider using 12'' block as he did,he used a concrete mix that contained fiberglass strands which he applied to both the inside and outside of the wall.pour your cores solid early and often with rebar.These were standard 12x8x16 cmu's.his house has been standing since 1996 and recently he has told me that he sees no sign of any problem.

[VOBB]

One question, if you pour the cells with grout and use rebar, why do you need concrete with fiberglass on the exterior of the block?

The strength of grout and rebar will make the wall ten times stronger (according to an engineer with the NCMA on a verbal basis) then a regular CMU wall with a weak mortar joint.

Are you just doing overkill and wasting your money?

************************************************** *******

Did your neighbor use the block only the exterior or on both the exterior and interior walls?

From my experience, I have seen dry-stack walls with just grout and rebar. I have taken samples of these dry-stacked walls and repeatedly slammed them to the ground without breaking them.

See the attached for a regular CMU wall with weak mortar joints when it was pushed from the lateral.
http://www.vobb.com/examples-inferior/Regular-cmu-weak-mortar-joint-100.jpg

Likewise, I have watched a man who built a home with regular CMU and dry-stacking. Yes, he did get it done. But you could have filled buckets with the amount of his sweat. In matter of effect, he calls himself the "King of Sweat". For this reason, we have VOBB which has a quality height and is based on 6", 12" & 18" in length. The key is, to design the home so you do not have to cut block, or as few as possible. Every time you cut a block, you are throwing down the drain the cost of the labor and part of the material. One successful VOBB owner asked, "Why cut it with a saw, when you can draw it with a pencil?"

VOBB is based on quality but designed to eliminate a lot of wasted labor cost.

Have a great day,
JG
Building better homes for our families, friends and neighbors
www.vobb.com
337-781-0705

[colonial carpentry]

Look at the strength and holding power of that durawall! it held down that last course of block like it was its job! Lmao!

[asmith555]

You need the surface bonding cement on drystack walls to hold the blocks in place during the pour. Otherwize some of the surface blocks may float away.

[Rich]

Bringing up old threads.. in response to rongaudier's comment about the cost of ICF blocks.. I'm buying them right now for 3.45 / sf for anyone that's interested.

[Shanley]

Just remember block perform very well in compression but not shear. Rebar and grout give cmu walls strength in shear. So your little picture is a little misleading