Pier & Beam versus Slab Foundation, Part 1

The two most common types of building foundations in north Texas and southern Oklahoma are pier & beam foundations and slab foundations (also known as "slab on grade" foundations). As a rule of thumb, most foundations for homes built during the 60's and before are pier and beam while those built later are slab foundations. So, why the change in foundation types, how exactly is each type of foundation constructed, and what are the pros and cons of each? We'll cover each question over the next several blog posts and, as always, you can ask us your questions about foundation construction, repair, and maintenance and we'll give you the answers.

Pier and Beam Foundations

Pier and beam foundations (sometimes called post and beam foundations) have a crawl space (typically at least 18 inches) between the home and the ground. The base of the building is uses a series of beams supported above the ground via piers. This type of foundation takes longer to construct than a slab foundation, but allows easier access to heating and plumbing utilities. (With a slab foundation, it may be necessary to break through the concrete slab foundation to service or repair plumbing and such.)

Since the piers separate the structure from the ground, the foundation is less susceptible (as compared to slab foundations) to damage from the ground shifting. When ground shifting occurs and the foundation needs adjusting, the piers are more easily adjusted than is a slab foundation.

The advantages of a pier and beam foundation are:

• Provides easy access to service plumbing, electrical and other issues under the house.
• In many cases, pier and beam foundation problems can be less expensive to fix than problems with slab foundations.
• Some remodeling projects and home additions are more easily accomplished with pier and beam homes than with slab foundations.
• Since the structure isn't resting directly on the ground and air is a natural insulator, the temperature within the structure may take less energy to maintain. That is, your home isn't sitting directly on the cold hard ground during the winter and, thus, your heating bills can be less.
• Many people feel that floors supported by a pier and beam foundation have a bit more give and are therefore more comfortable. This is not to say the floor rebounds like a trampoline as you walk across it, but there is a difference according to many homeowners.

The disadvantages of a pier and beam foundation include the following:

• Pier and beam foundations take longer to construct than slab foundations. This increases the cost of the home or other structure.
• Floors supported by pier and beam foundations may creak and move.
• Broken vent screens and insufficient other barriers may allow bugs and rodents to get under the structure.
• Pier and beam foundations have to be vented properly to reduce moisture. Sufficiently high moisture levels can lead to mold, rotting wood, musty smells.

In our next post, we'll discuss slab foundations.

Get more information by visiting www.AceFoundation.com.

Do Steel Piers Rust?

"Do steel piers rust?" That's not an uncommon question.

The short answer is "No."

Steel piers are galvanized, which prevents rust. When steel is galvanized, it is dipped in molten zinc, which forms a chemical bond to the steel. Galvanized steel products gain good protection against rust and failure when used above or below grade. You can tell when an item has been galvanized, due to its unique silver color.

Wikipedia has a pretty good, technical description of galvanization. You can read it here.

Get more information by visiting www.AceFoundation.com.

A Great Soaker Hose Tip

In our last post, we discussed soaker hoses and regulating the moisture around and under your foundation. This time around, we have a tip for a problem many people have when using soaker hoses.

What do you do if, by the time you've connected all your soaker hoses together, there's not enough pressure at the end of the last hose?

The first thing you need to do is understand why this occurs. The pressure is dropping at the end of the hose because there's too much hose for the amount of pressure provided at the water spigot. By the time the water reaches the farthest lengths of the hose, the pressure has dropped so much that the water isn't forced out the tiny perforations in the soaker hose.

The next thing to do is to see if there are additional water spigots you can use. Instead of stringing all your soaker hoses from one spigot, split your soaker hoses among two or more. If you're afraid of using all your spigots for just soaker hoses, you can purchase multi-headed spigots that attach to the spigot coming out of the wall. That way, you can hook up the soaker hose and still have a connection free for other uses when you're not using the soaker hose.

If you can't use additional spigots, you can alternate traditional hoses with soaker hoses. Since a traditional hose doesn't lose water from the tiny perforations like a soaker hose does, then it maintains a higher pressure through its length. With a combination of soaker hoses and regular garden hoses, you can reach the farther parts of your foundation and still maintain adequate pressure. You may have to run two sets of alternating hoses (call them Line A and Line B). Make sure when setting the two lines that where Line A's soaker hose(s) alternate with Line B's soaker hoses. When it comes time to use the soaker hoses (about once or twice a week, depending on soil conditions), connect Line A and run for 30 or more minutes, then disconnect and run Line B for 30 or more minutes. In this way, you'll water the entire perimeter of the foundation, yet each hose is only responsible for half the task.

Get more information by visiting www.AceFoundation.com.

Soaker Hoses, Revisited

With all the rain we had in September, you might think we're nuts to be talking about soaker hoses again, but there's a good reason.

Soaker hoses are one of the best tools in the homeowner's toolbox for regulating soil moisture. Now that we're approaching the end of summer, it's a good time to get outside and check your soaker hoses for proper placement and overall condition. Make sure the soaker hose is buried about three inches deep and about six inches from the edge of the foundation so that the soil is soaked evening.

Do not place the hose against the foundation. Water placed next to the foundation (say, provided by a soaker hose placed against the foundation) runs through the cracks and pools at the bottom of the grade beam. (The grade beam is the thick portion of the foundation that is under the exterior walls.) The accumulation of water at the base of a foundation over time can reduce the soil's capacity to bear a load. When the soil loses enough load bearing capacity, the foundation will sink and your house can be damaged!

While you're checking the soaker hoses' position, don't forget to check the condition of the hose. Soaker hoses are pretty simple things. If you find a leak, tape it using duct tape (or similar tape -- ask at your local hardware store for appropriate substitutes). If the soaker hose is cracked or leaking from one of the fixtures or connections, replace the hose. The few dollars you spend on a new hose is a whole lot let than you'll spend on foundation repair.

Do you have questions about soaker hoses and your foundation? Then ask us!  In fact, you can ask us anything about foundation construction, repair, and maintenance. We love questions, so ask away!

Get more information by visiting www.AceFoundation.com.

Root Barriers, Revisted

What's a root barrier and why is it important? Root barriers are physical barriers that redirect tree root growth downward, thus eliminating surface rooting that can damage foundations, sidewalks, driveways, and other hardscapes.

Remember, roots travel away from the tree trunk as the tree searches for water. Often times, tree roots gravitate towards the building foundation. Once roots reach the foundation, they may press into the foundation and break it, lift it, lower it, or otherwise shift it. Each of these movements can cause significant damage to your foundation.

Also, note that the roots can suck the moisture from the soil, thereby leaving it dry. Dry soil contracts, which can cause the foundation to shift. This is another unpleasant and damaging side effect of tree roots interacting with your foundation.

A root barrier can prevent roots from causing this damage to your foundation.

Root barriers surround the structure and prevent tree roots from getting under the foundation. While you may consider a root barrier a "nice to have" rather than a necessity, keep in mind that root barriers are usually much, much less expensive than foundation repair.

Ace Foundation installs a tough, flexible material designed to resist cracking due to soil movement or new root pressure. (Other foundation repair companies may use concrete or plastic (corrugated vinyl, for instance), but we've found these to be less reliable than the material we use. If another foundation repair company recommends concrete, think back to any number of sidewalks you've seen, cracked and pushed up by tree roots!

Learn More with Our Root Barrier Video

We've prepared a great video which shows exactly what root barriers are and how they protect your home or business' foundation.

Watch the Video

Get more information by visiting www.AceFoundation.com.

Piers for Pools (cont'd)

This is the second part of a post concerning foundation piers for swimming pools. If you missed the first part, take a look at last Tuesday and get caught up.

Steel piers are the preferred choice when installing or augmenting piers for swimming pools. The advantages you get with steel piers for home and commercial & industrial foundations apply to swimming pools, as well. Steel piers don't require curing time like concrete does, so construction time is reduced. Steel piers require a smaller "footprint" when they are constructed. Steel piers are incredibly sturdy and a proven reliable solution.

One important thing to note about piers for pools is that the piers shouldn't be anchored to the pool. Why, you ask? Because the pool must be free to move a little bit. The pool is going to move no matter what; the key is that it's only allowed to move so much before it is stopped or stabilized. If the pool is anchored to the piers, then when the soil around and under the pool expands or contracts and pushes or drops the pool a bit, the pool is going to crack where the piers are anchored to it. This is because the pool is trying to move but is tied down at the piers.

Be sure to check out some of our slide shows for piers for pools and let us know what you think.

Get more information by visiting www.AceFoundation.com.

Piers for Pools

We've talked about piers for pools before, but now's a good time to recap. If you have a swimming pool, then no doubt you've had a chance to enjoy it. Did you notice anything different about your pool while you were out there?

For instance, does the water line appear to be at a kilter? In other words, is it not level? If this is the case, then part of the pool is higher than the other, which gives the appearance of the water being lopsided. It may be subtle, maybe an inch or two across the entire pool, or it could be more pronounced. Whatever the degree, this means that one end of the pool or the other has shifted up (down). Much like when you hold a glass of water and tilt the glass, the water stays level but runs diagonally across the glass, your pool is tilting and the water appears to run diagonally (though, not as dramatically as that glass of water).

This is the same behavior as when part of the foundation of your house lifts or drops. It means that the soil in or around your pool (or building foundation) has swelled or shrunk and the foundation has moved as a result. And, just as with your house, the shifting of your pool can cause problems. Sometimes the problems are cosmetic. For instance, the lip of the swimming pool can rise above or drop below the surface of the sidewalk or deck around it. On the other hand, more serious problems can occur, such as stressing and breaking the plumbing or creating cracks.

What can you do when this happens? Well, you can address it just as you would with your residential foundation or commercial foundation: You can level and stabilize your swimming pool with foundation piers. You can prevent further problems and correct existing ones when your swimming pool is back to level and no longer moving in unpredictable directions and amounts. Adding piers to the pool or augmenting existing piers with new ones is the best way to protect your investment in one of the most expensive additions to your home, and it insures that you and your family can enjoy your pool -- rather than regretting it.


In our next post, we'll discuss the specifics of steel piers for swimming pools.


Get more information by visiting www.AceFoundation.com. Or, feel free to ask us anything! We love questions -- and we've gotten some really good ones lately. Fill out our Ask Us Anything form and look for your answer in your email. Plus, we'll update this blog and our websitehttp://www.acefoundation.com with the questions and answers we've received and given over the last few months.

What to Do After Your Foundation Has Been Leveled

We discuss quite often how to maintain your foundation and prevent foundation failure. Just as important, though, is knowing what to do after you've had foundation work done. Below are tips you should follow after your foundation has been leveled.

1. Maintain a consistent moisture level in the soil adjacent to the slab foundation. You can keep the moisture content consistent by evenly watering next to the foundation slab, especially during dry periods. There are a couple of ways to do this.
   
   First, use a buried foundation watering system with the water line buried twelve inches away and at the depth of the grade beam. The system should have a rain cutoff switch and a flow control box with a filter (the filter prevents sediment from clogging the line).
   
   Or, put soaker hoses around the edge of the foundation, seven to twelve inches from the grade beam. Remember to use the soaker hoses on a schedule or buy a battery-operated, programmable timer.
   
   Of the two methods above, the second can waste more water due to evaporation and run-off. Finally, keep in mind that watering the foundation does not fix existing foundation problems -- it's only a maintenance method.
2. Make sure water drains away from the slab perimeter. Eliminate all standing water near the foundation slab. This evens out the moisture content underneath the slab and lessens soil movement beneath the slab foundation.
3. Be sure large trees near the concrete foundation slab get plenty of water. Avoid high growth of dense vegetation near the concrete foundation slab, as well. When you water trees -- especially in dry periods -- you help even out the soil's moisture content beneath and around the foundation slab.
4. Make sure that the slab is at least three to four inches above the finished ground, including flowerbeds and other landscaped areas. The flowerbeds should slope away from the slab. This prevents water from draining to underneath the foundation and keeps water from pooling at the edge of the foundation.
5. Make sure the plumbing system, potable water lines, and sewer lines are checked periodically for leaks. A licensed plumber can perform these tests for you. Remember, water leaks cause differential moisture content and ultimately contribute to foundation failure. 

We hope you find these tips useful. A lot of them are also good maintenance ideas even if you haven't had your foundation leveled. Get more information by visiting www.AceFoundation.com.

Waffle Slab Foundation

Waffle slab prior to concrete being poured.

In our last blog post, we discussed post-tensioning cable foundations. This time around, we'd like to discuss another development in building foundations, waffle slab foundations.

Waffle slab foundations are formed when beams are poured throughout the interior until the pattern resembles a waffle. While the jury may still be out when it comes to how effective post-tensioned cable foundations are, waffle designs have shown themselves to be more likely to create a stiff foundation which results in the whole house moving, rather than just a certain portion of it.

Another view of a waffle pod slab prior to concrete being poured.

Waffle pod foundation construction uses less concrete than traditional methods of edge beam and internal beam. This keeps construction costs down. Labor costs may be reduced, as well, since significant trenching (which is labor intensive) can be eliminated.

Unfortunately, this type of foundation requires more piers than traditional slab foundations when it comes time to level things. More piers means more expense. Please keep this in mind when you are considering the savings in construction — you may end up giving it all back when it comes time to fix the foundation.

Get more information by visiting www.AceFoundation.com.

Post-Tensioning Concrete Foundations

Traditional rebar (but blue!) in place and ready for concrete to be poured for a foundation. Photo by Flickr user GeekMojo

Traditionally, concrete slab foundations are reinforced with steel bars, called re-bar (or rebar) -- short for "reinforcing bars." This technique of reinforcing concrete and similar materials originated in 1867 with a French florist named Joseph Monier. His experiments in making a stronger flower pot ultimately led to embedding reinforcing bars in the pots as they were formed and before they were kiln dried.

Post-tensioning concrete foundations are the next wave beyond traditional concrete slabs. With post-tensioning slabs, high-strength steel strands or cables, typically referred to as tendons, create a grid of steel cables that actively support the slab. Traditional rebar construction is "inactive" only really helps keep the slab intact after the slab has cracked. Slabs with post-tension cables are usually thinner and this can cut down on curing time and, ultimately, construction costs.

Post-tensioning being used in the construction of a concrete bridge for a highway. Photo courtesy of the Kansas Department of Transportation

Post-tension concrete foundations are used not only in home construction, but in commercial construction. Since this method combines structural integrity and thinner pads, office buildings can have thinner floors but retain comfortable ceiling heights, which in turn reduces total building height and weight load.

Caveats

With all that said, one must keep in mind that post tension foundations do not solve the underlying soil's ability to handle moisture. That is, just because a home or business is built on a foundation with post tension cables, it doesn't mean that the soil on which that foundation rests quits expanding and contracting as the moisture content changes. Post tension foundations can still shifting or even failing. You must still perform essential foundation maintenance, such as maintaining a consistent moisture content within the soil, keep tree roots at bay, and watching for signs of foundation failure like cracks in the wall, stuck doors and windows, wrinkled wallpaper, and popped or loose floor tiles.

If a builder tells you that a post tension foundation solves all your problems and you'll never have to worry, then run — don't walk — and find yourself another builder! Remember, the builder is trying to sell you the house, but you're the one who must live with the purchase for years to come.

Have questions or want more information? Then visit us at www.AceFoundation.com or give us a call at 972-272-1900.