Precast Walls vs Poured Walls


  #1  
Old 03-14-23, 04:19 PM
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Precast Walls vs Poured Walls

Hello,

I am considering building my new house in concrete.
I was looking at ICF, but the high material cost of Styrofoam and plastic webs are not rectified.
So, I thought having the walls poured conventional until I came across precast concrete walls.
While I know that the conventional poured walls are complete surrounded by rebars, I cannot get my head around on how these precast walls get mounted together. They are just sections of concrete sheets.
  • Are they bolted together at the seams?
  • Are they as sturdy as the conventional poured walls?
  • What is the advantage of these precast walls?
Any insights from the specialists are appreciated.

Thank you.
 
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Old 03-14-23, 05:21 PM
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I have Superior brand pre-cast concrete walls in the first level of my house. Built in 2001 and there are no cracks or water leaks so I'm happy so far.

Installation of the wall panels so is all their. The site is prepared and a thick layer of crushed stone is leveled out where the walls will go. They put a heavy bead of sealant/adhesive between each panel. Then they get bolted together. Installation took about half a day. Then the last bit of strength comes when you pour a concrete floor inside which locks the bottoms of the wall panels in place. Then the floor/ceiling locks in the top of the walls for a strong box construction. I have one very long straight wall so their Engineering specified that I build a sheer wall (no biggie).

One benefit of pre-cast walls is price and speed. Manufactured in a factory and purchased beforehand the price is known and fixed. No overruns or surprises for extra money. It's also fast. It literally only takes hours for the panels to be erected on site.

My brand walls came with R5 rigid insulation built in (it was 2001, I think their specs have changed). Then because of the thickness of the wall cavity when you add fiberglass or other insulation you can get a really good R value. When I bought them the walls were rated as waterproof as installed but I also did a traditional waterproofing membrane on the outside, belt and suspenders.

CONS:
My biggest complaint about pre-cast is that you pay more to get less... There is a base price for the solid wall. Then you pay additional for openings. So, doors and windows drive up the cost even though you are getting less.
The furring strips cast into my wall's studs was only 1/2 or 5/8" thick. Standard length sheetrock screws were too long but I think they switched to thicker furring strips to avoid the issue.

Another con is wiring and plumbing. They do cast in holes but they can't be moved so you have to either plan very thoroughly and accurately or work with the holes you get. It's also very difficult to pull additional through finished walls.

----
I also considered most other methods. Poured walls were my first choice but there are no contractors in my area so installation would have been expensive. CMU can be slow and because everything is done on site there is a chance for cost overruns and CMU requires proper waterproofing treatment to remain dry. ICF was a real contender but it can be pricey and you have to somehow protect the walls inside (optional) and out which adds to the expense and they need treatment to prevent insects from nesting in the foam. But, do you own research because your pro's and con's may be different than mine.
 
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Old 03-14-23, 05:47 PM
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Thank you for your inside.
With ICF you will lose all the benefits of concrete in the interior. Styrofoam does not retain hot or cool air when heating and cooling the house. I am from Europe and used to 14 inch thick exterior brick walls and these thin wooden framed walls IMO don't do anything in soundproofing, energy efficiency, or high winds.
And with a good drill bit and hammer you get through every wall and these walls gives you a better comfort. I just can't decide which walls I do. Poured or precast.
 
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Old 03-15-23, 05:14 AM
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"...wooden framed walls IMO don't do anything in soundproofing, energy efficiency, or high winds."
Masonry walls are terrible for efficiency. Look up the R value of any masonry; concrete, rock, brick. It has thermal mass but but the extremely low R value makes them very inefficienct. Precast walls to to great lengths to INSULATE the masonry/concrete from the interior of the house. If you do a poured wall it is common to build a separate wood wall to hold insulation.
 
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Old 03-15-23, 05:53 AM
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Only if you are talking about solid bricks. In Europe we use hollow bricks, and they have a good efficiency. The bricks which are used here in the USA are only good for walkways and sidings.
The EPS or stonewool (Rockwool) insulation will be glued on the concrete walls.
I worked with insulation back in Germany when I was in construction, but we had no precast homes. All homes are built with red brick blocks.


 
 

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