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Getting your home started on the right footing

 

Poured-concrete foundations--how difficult can they be?

One takes a bunch of boards and plywood and nails them together to make a form system and then pours in some concrete.  How difficult can that be?

rotted form tie and point of water intrusionTo be honest however, getting the foundation right is very important to getting the whole house done right.  Perhaps this could be known as getting your home started on the right footing.  There are so many things that have to be considered before you nail all those boards together.

1.     Excavating to the necessary depth and down to undisturbed soils  is criitical.  Both of these can be difficult or easy depending on where you are digging. Of course getting the foundation hole all dug out and nice and level is a good part of the battle, but an ill-timed rain can make a mess of it that can lead to areas of “disturbed” soils.  These mushy areas then have to be excavated to be filled with more costly concrete—hopefully.  Many builders however just ignore the mushy spots and just pour away.

2.     Depending on the soils you are building on, you will have to think about how wide and how tall the footing under the foundation wall is going to be.  Geo-technical information will give you this information and is usually spelled out on the plans.

3.  Will the finished height of the foundation be high enough to keep wood siding and trim components far enough above grade?  This is a very commonly missed consideration.

4.     How thick is the foundation going to be?  This will also be spelled out on the plans.

5.     Have you installed a concrete releasing agent on the forms so that the concrete does not stick to the forms?  Whoops!

6.     What strength of concrete and what size aggregate will you be using, as well as how much slump is allowed? (Makes you want to slump into your arm chair by now doesn’t it?)  However slump will predict how many shrinkage cracks you end up with.

7.     How much rebar will there be in the footing and foundation and what different sizes will be required?  The house plans will tell this.  You do have plans don’t you?

8.     Will the foundation and footing be poured all together or will the footing be poured first and the foundation poured on top of the footing later.

9.     You will also have to consider all the foundation anchor bolts and imbedded strapping etc.

10.     And don’t forget the Concrete Encased Electrode.

11.  There can also be penetrations that have to be considered like: crawl space vents, window openings, door openings, ductwork openings, plumbing pipe openings, gravity drains etc.

12.   There can also be decorative items that have to be installed on the inside of the forms.  You know---the lines that make the concrete look like something else?

13.   Is the top of the foundation perfectly level? You better pay attention to this if you don’t want your house framing that is going to sit on your foundation to be a nightmare.

14.   Have your protected the wall from evaporation or freezing after the concrete is poured?

15.   Are all corners the correct angle?  For example, in a rectangular foundation, the diagonal measurement from corner to corner must be “precisely” the same.  Likewise, the lengths of opposite sides must be exactly the same.  If they are not, your diagonal measurements will be useless.  This can get very complicated when you are talking about angles greater than or less than 90 degrees and if there are many zigs and zags.  If you have not managed all this properly---just wait until you get to the roof structure!

16.  This list is just a few of the considerations to get you thinking about how simple the foundation is.

Today I want to talk about #5.

In my opinion it is best practice to install the foundation as a “monolithic pour.”  That is when the footing and the wall are all poured as one unit.  This method eliminates any cold joint that would be present at the footing/wall connection if they are poured separately. In this method of pouring the foundation, wood elements are used to span the boards used to make the footings, and the forms for the walls sit on top of these cross-boards.

 Eventually, when the footing and foundation form boards are removed the spreader boards (cross-ties) remain in place.

footing crosstieOver time these boards will rot or become infested with wood destroying insects.  They can also lead to points of water intrusion or become vermin entry points.  Inspectors routinely call for these wood components to be dug out of the concrete and sealed with expansive concrete to prevent leaking and keep vermin out of the crawl space. They are considered conducive to wood destroying organisms--and are reported as such by any Licensed Structural Pest Inspector.

One solution to this problem is to make the spreaders (cross-ties) out of foundation grade pressure treated lumber.  On a recent foundation I noticed that the builder had used pressure treated lumber.  As I approached, the foundation, I could see a sticker on the end of one of one of the boards and I could read the words “Pressure Treated Wood.”

Well that was interesting, because my experience with foundation grade pressure treated materials told me that the color of the sticker and the appearance of the wood (color) were not quite right.  Also, in the NW, most foundation grade pressure treated lumber has “incise” marks on the surface to aid in getting the preservative into the wood. (This is not true for folks on the East Coast that have access to foundation grade pressure treated Yellow Pine.)

When I got closer and could actually read the sticker, I could see that it was pressure treated lumber and that it had a “lifetime limited warranty.”  The part that said for “Above Ground Use” meant that someone basically wasted their time and money on materials that will ultimately fare not much better than untreated wood.

cross-tie

These cross-ties now have a “limited lifetime warranty” as opposed to a “lifetime limited warranty.”

Poured concrete foundations--how difficult can they be?

 

Charles Buell, Real Estate Inspections in Seattle

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Seattle Home Inspector

 

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Comment balloon 32 commentsCharles Buell • August 03 2014 03:17PM

Comments

Good morning Charles.How extensive and thorough. # 5 is something I knew nothing about but it clearly makes a major difference.

Posted by Sheila Anderson, The Real Estate Whisperer Who Listens 732-715-1133 (Referral Group Incorporated) about 4 years ago

If one has entered new construction and observed an entire wall buckling inward, one would know.

 

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley, Homefinders.com, MD & VA Homes and Real Estate) about 4 years ago

Wow, a board sticking out like that should have been caught long before you did!  I bet you do see some crazy things.

Posted by Paula McDonald, Magnolia Realty ~ Granbury, TX 936-203-0279 (Magnolia Realty ~ Granbury) about 4 years ago

Sheila, it has been a very long time since I had to think about such things--but some of it came back pretty easily

Lenn, I have seen a few "blow-outs" in my day.  They are almost always due to carelessness.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

What a great title!  This is one job that should not be a diy job!

Posted by Sharon Tara, New Hampshire Home Stager (Sharon Tara Transformations) about 4 years ago

Paula, the board is pretty normal---should be foundation grade as best practice however.

Sharon, most people don't like getting dirty

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

Good day Charles, a lot of people don't want to bother fixing them. Its so important and is labor intensive. Not great if you are 6'9". I bet you have seen a few  footings and foundations which are under the required thickness with re-bars that are too thin. 

Posted by LLoyd Nichols, SW Florida Homes (Premier Florida Realty of SWFL) about 4 years ago

Obviously, just slapping boards together and pouring concrete is not a good idea! As you've pointed out, a lot goes into ensuring a good foundation.

Posted by Kat Palmiotti, The House Kat (Grand Lux Realty, 914-419-0270, kat@thehousekat.com) about 4 years ago

When the foundation isn't right, it reminds me of that saying, "When mama isn't happy, nobody is happy!" 

Posted by Myrl Jeffcoat, Greater Sacramento Real Estate Agent (GreatWest Realty) about 4 years ago

You always have such great information, Charles.  Just reading your posts makes me a more aware consumer!

Posted by Ron Marshall, Birdhouse Builder Extraordinaire (Marshall Enterprises) about 4 years ago

Here is the definitve post on the subject matter.Well done and shared. thank you

Posted by Richie Alan Naggar, agent & author (people first...then business Ran Right Realty ) about 4 years ago

Lloyd, by the time I see them there is no way of knowing what rebar they used

Kat, yes--exactly---even more than my little list

Myrl, ain't that the truth---love the quote

Ron, thanks---glad you find them useful

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

Richie, it is a start anyway

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

Wow, this is a ton of great  information....looks like someone could have used it!

Posted by Kristin Johnston - REALTOR®, Giving Back With Each Home Sold! (RE/MAX Realty Center ) about 4 years ago

In my case and it was the only time I ever saw it, the builder had poured the concrete foundation and backfilled the following day.

The concrete had no time to cure.

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley, Homefinders.com, MD & VA Homes and Real Estate) about 4 years ago

Kristin, it may or may not be a problem over time.  In some respect it has to do with what was done on the outside.  If the boards were cut off at the exterior and properly sealed, it is likely that they would never be an issue.  The inspector typically can't know this---so we make the necessary comments/recommendations to cover our butts

Lenn, I never liked the idea of backfilling prior to getting the floor system in place.  Always seemed risky to me.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

I have just the friend who is needing this post right now Charles! Wouldnt you also say foundations poured in the summer are less likely to crack than ones poured in winter conditions?

Posted by Annette Thor, Residential & Commercial Real Estate Broker in CT (Connecticut Homes and Commercial Fairfield Cty,CT reinct.com) about 4 years ago

Annette, it depends where summer is and where winter is.  In your neck of the woods where you have fairly harsh (hot) summers and equally harsh (cold) winters the proper precautions must be taken to avoid problems with the concrete pour.  Cracks have a lot to do with too much water in the mix and too much drying potential.  Ideally you want the concrete to cure as slowly as possible and both cold and hot have an effect on this.  In winter there are additives that can be used as well as it must be adequately protected from freezing regardless.  Both extreme winter and summer conditions can be difficult to control for optimum results.  That said, I think summer is easier to control in my experience.  Getting the correct mix, with the correct amount of water is critical regardless.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

Charles, thanks for the foundation lesson today.  Before reading this I would probably have undertaken such a project.  Now, no way.

Posted by Stephen Weakley (Nationwide Mortgage Services) about 4 years ago

Gee, those sure are a lot of questions.  It's just concrete.  You can get the bags at the hardware store right?  Why not just follow the instructions on the bag?  That's probably way easier than all those other steps.

I'll be at the 7-11 again tomorrow.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 4 years ago

I love the monolithic pours, but there are few contractors that do that here. We still do a footing, stemwall and then a floating slab. Three seperate poors and more labor, time and money.

Posted by Than Maynard, Broker - Licensed to List & Sell - 405-990-8862 (Coldwell Banker Heart of Oklahoma) about 4 years ago

Stephen, there is certainly a lot to learn

Jay, instructions?  It comes with instructions?  Whodathunk

Than, it typically takes more time to set the forms for a monolithic pour so many builder will opt for the other approach

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

Hi Charles - Thanks for the primer on foundations - interesting and useful. I showed a home last night that had an interesting foundation designed to deal with expansive clay soils, which occur here fairly often and require site soils samples for any new build.

Posted by Dick Greenberg, Northern Colorado Residential Real Estate (New Paradigm Partners LLC) about 4 years ago

Charles, your posts are always a new lesson for me - learning from an expert. (and sometimes I boast about my deep knowledge in front of my clients..lol!)

Bookmarked, for sure.

Posted by Praful Thakkar, Andover, MA: Andover Luxury Homes For Sale (LAER Realty Partners) about 4 years ago

Charlie, great post as usual.

Posted by Donald Hester, NCW Home Inspections, LLC (NCW Home Inspections, LLC) about 4 years ago

The foundation is pretty important to the structure, we better get that right Charles. I love that list and hope you cover many of the other points as well.

Posted by Tom Arstingstall, General Contractor, Dry Rot, Water Damage Sacramento, El Dorado County - (916) 765-5366, General Contractor, Dry Rot and Water Damage (Dry Rot and Water Damage www.tromlerconstruction.com Mobile - 916-765-5366) about 4 years ago

Good info Charles:

This definitely does not sound like a do it yourself project.  I take it you have probably seen some of those

Posted by Jennifer Manchester, GRI, ePRO, ASP - Broker/Home Stager (Suburban Properties of Charlotte, LLC ) about 4 years ago

Dick, now there you have another whole consideration that I didn't even touch on directly---but is part of any soils analysis necessary for just about any site.

Praful, I am more impressed by what I don't know

Don, thanks

Tom, perhaps one day

Jennifer, on occasion

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

Don't see that out this way. Typically footings are poured first, then the wall.

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) about 4 years ago

Jim, having grown up in your area, I would be willing to bet that the reason you don't see mono-pours is because there was a time when nearly all foundations were CMU.  Habit takes over

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

I see many poured foundations, even on houses built in 20s. I find CMUs to be more regional. Some parts of the state tend to have them, while others do not. 

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) about 4 years ago

It would be interesting to know the patterns.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 4 years ago

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