If you build a wall from blocks, you need to transport the blocks, mortar, and employ a skilled worker (a mason) to set the blocks.
In contrast, for a pored wall, you set up the forms, pourthe concrete, then remove the forms.
Which is cheaper to do? It seems to me, that a poured wall would be easier/cheaper to construct-which is?
Block is cheaper. That’s why light-industrial buildings (a garage, say) are built with block.
Around these parts, basements with block outer walls (which double as the home’s foundation) have a reputation for leaking in water. I have seen it many times. I would never buy a house with a basement w/ block walls; only poured concrete for me.
It’s not a strict case of one is always cheaper/better than the other. For concrete you also need to make sure it’s properly mixed, that it’s allowed to set/cure, etc. One mistake and you’ve ruined a fairly significant sized piece, if not the entire wall. Masonry blocks have their drawbacks, as well. A block building is the second-last place (except for a mobile home) I want to be in a tornado.
CMU wall is typically cheaper but it is not necessarily a better wall. But again it all depends on what the wall is for. CMU can be used as a basement wall, but I wouldn’t unless you had a product that allowed it to drain such as a miradrain or something like that. Actually both products are porous so some caution should be taken.
If I was you I wouldn’t choose CMU vs Concrete based on price, but rather based on what the intended use of the wall is. Both products are good products used appropriately. Sometimes a CMU wall is a much better choice and sometimes Concrete is.
Around here poured concrete is cheaper, and has taken over the market. But in the past blocks were very common. It appears the cost of a mason has risen to the point where a poured concrete form takes the price advantage. About 10 years ago I saw a development of new houses in Pennsylvania done with blocks. I’m not sure what drives the decision in different markets, but it sounds like both methods are close enough in cost that small factors will drive the decision one way or another. I’m sure practitioners of both methods will claim superior quality in their product.
Block is cheaper, because they use much less concrete than a solid poured wall.
Also, the hollow spaces provide some insulation, so the builder can save money by using less insulation on the wall.
You still need to transport concrete if you pour a wall. A friend is pouring concrete floors in his basement and we’ve been lugging bags of concrete around. Much heavier than cinder blocks.
Driving up to the site and pouring the wall into place is a heckuva lot less general effort than moving pallets of bricks around, ad then transferring them a few at a time into place. Bricklaying is the least of the labour.
However, as pointed out, the amount of concrete - a solid wall with reinforcing is a lot lot stronger than a bunch of blocks, which essentially are a pair of 2-inch walls. In some areas, earth is mostly clay and will expand/contract with water content. Unless a lot of relief is built in (maybe sand fill for 2 feet or more, styrofoam around the exterior) this expansion will crack even a concrete wall. drainage is also an issue, as mentioned.
Construction of forms benefits from economies of scale. Custom forms are labour intensive. The same forms used for a hundred buildings are cheap.
Another construction I have seen involves using foam bricks like leggo; essentially a pair of foam sheets with plastic spacers. Place the reinforcng rods inside the stacked bricks, then pour the hollow center with concrete. Much cheaper than forms, and faster, and less labour intensive, less waste than wood forms. As a bonus, the foam stays in place as insulation and the walls of he house are pretty much one solid chunk.
You don’t get a strong structure that way. Building code around here requires hollow blocks to be filled with mortar or concrete, and reinforced with rebar.
Making a comparison based on a skilled mason being required vs. just setting up forms is a bit misleading.
It does take a lot of skill and practice to lay a good wall with block. And any jerkoff can set concrete forms, but as mentioned above, it’s easier than it seems to do something that can result in seriously flawed wall.
My FiL is a structural engineer, and I used to visit plenty of construction sites back when I worked for him. In every building I saw, all of the structural elements - pillars, beams, ceilings, load-bearing walls - were made of reinforced concrete, while everything else was made of either cinder block or pre-cast elements.
That is insulated concrete form construction.
Another technique is tilt up panel construction. The walls are poured as horizontal concrete slabs and then tilted up to form a vertical wall section.
You are talking about ICF. More expensive, not cheaper than traditional forms. It is more labour intensive, and slower because of that. Concrete forms generally are re-useable systems so there is very little waste anyways. The interior of the wall must be drywalled for fire code. Electricians consider it a pain in the ass. The major benefit of ICF is its insulation, half of which is on the inside where it does less good.
Do not get me wrong ICF is a good product, but people try to sell it like it is the enviro wonder solution - and it isn’t. It has become increasingly popular for party walls in multifamily housing because of its superior sound insulation and the comparative difficulty of traditional forming on the main and second floors of wood framed structures.
I have built several foundations with it and in all honesty a traditionally poured concrete foundation with the insulation fastened to the outside (where it does the most good) before back-filling is a better green solution.
I joined SD just now after reading some of the comments in this thread. I don’t agree with many of the comments. An inexperienced home builder can build a very inexpensive concrete block wall of very high quality by using a method called ‘dry stacking’ which has been around for 100 years. You stack the blocks with no mortar in between them, fill the blocks with rebar and concrete, and smear a paste made of concrete and fiber on the walls. The paste is called SBC (Surface-Bonding cement). This makes for and incredibly strong wall. Incredibly strong. Fit for load bearing. And very inexpensive with no need for skilled labor. Just FYI.
There are all kinds of blocks in different dimensions. Block, also called CMU, generally comes in widths of 4”. 6”, 8”, 10”, 12”. In some areas of the country 14” and 16” block widths are also available. As you can imagine the greater the width of the block the greater the cost of the wall.
Also you have standard block and then there is decorative block which is more expensive. Most people have seen decorative block a thousand times in their life, but not realize what it is.
Also there are reinforcing requirements that may apply in your area to a block wall. This means putting in rebar and filling the cells with grout to strengthen the walls. This is determined by local building codes. This raises the cost of block walls.
There is also block that is specifically made to have concrete poured into the block, complete with rebar channels.
For concrete rather than using panel forms you can purchase ICF type forms. This is a Styrofoam product that is very light, is laid like a CMU block, and designed to have concrete poured into it. Once again complete with rebar channels.
So in general a block wall is less expensive than a concrete wall, however depending upon the local conditions, building codes, seismic and other requirements the price per SF can cross so that concrete could be the less expensive option.
It would help a bit if we knew whether we were talking about below-grade walls for a residential basement, above grade walls for a residence, either of the above for a tall building, structural walls for a warehouse-like building, or long but low divider walls between properties or along roads.
Different missions have different requirements and therefore different best practices. I’d also bet the relative costs of labor and of concrete have an impact. And they aren’t the same nationwide, much less worldwide.
So ralph, what are you really asking about?
It’s been over 3 years since he asked, doubt he’s still following the thread.
In Florida we have poured concrete foundations and block walls above grade, but then we don’t have basements.
Damn! Thanks. I *hate *it when I do that.