The Montrose Gold Team Blog

What Kind of Soil Does Your Home's Foundation Sit On?

You might be thinking...

"Who cares?".  

Think again!

The soil and foundation combination are the most important parts of your home.  They hold up your entire home and keep it square and hopefully level as well.  But square and intact is the most important. 

You really don't want your foundation to move at all, but if that is not feasible or cost effective you can at least design it to move in unison.

 

 

So how do you know what kind of soil you have or what type of foundation or what shape it is in?

Investigation, research and a professional opinion.  Here the "professional opinion" should not be your Realtor's.

You need a Geotechnical Engineer or a Geologist and then a structural engineer for the foundation.

What can YOU look for before hiring an engineer?

• Foundation cracks
• Sunken areas around foundation where water settles.
• No gutters or gutters with spouts dumping right along the foundation.
• Signs or smells of mold or mildew.
• Drywall cracks
• Uneven or sloping floors
• Doors that don't close or line up properly
• Windows that don't open and shut properly
• Things that look out of Square with one another (e.g. Door Trim Above door looks crooked)
• On raw ground - look for cracks, wet areas, white areas (especially in Montrose Colorado), slide areas, rock fall hazards (are you under a cliff or steep slope with big rocks on it. - BTW I have seen boulders bigger than cars halfway in houses in Telluride CO. - they fell/rolled down the hill and crashed into the unsuspecting home), etc.
• Ask your Realtor if he/she sees anything funny looking, but don't rely on their opinion, just use it for clues to potential further investigation by the professional.

What does all this really mean if I see or smell problems?

Typically it means there has been movement of some type.  How recent and the cause are what is most important to determine.  Is it still moving?  Has the problem been fixed to stop or minimize further damage or movement?   Is the foundation structurally damaged where the crack is causing further strain and stress on adjacent components?   

These apply to new or existing homes.

These soil and foundation questions are all very important to ask, whether you own your home now or you are just thinking about buying it. 

Planning to Build a New Home or Addition?

Step 1 - Get a Soils Assessment Study

It is critically important to protect your investment when building a new home to have a soils study done, unless it is just so obvious, like solid rock, that you are certain you don't need it.  Even then I would say it was worthwhile (good insurance), because it is Step One.

Step 2 - Give the Soils Data to the Structural Engineer

Give the Soils Data to your foundation engineer so they can determine the bearing capacity of the soil (how much weight can it hold before it will give).   

If it is lower, they may have you over-excavate and backfill with good compacted material, or use piles, pad and pier, post tension slab, waffle slab, etc.

If it is high, like solid rock - they may be able to save on foundation design and costs. (e.g. When I did communication towers for a living... we anchored some directly into solid granite or other rocks atop mountains by drilling holes and using epoxy to secure the anchor bolts directly to the rock. - no foundation necessary.)

Step 3 - Make sure your Contractor Builds What was Designed!

The best design in the world is worthless if it isn't used during the construction.  Not all but some contractors I have witnessed show blatant disregard for the "directions" - they just do it their way.  Maybe their way has worked on the last 100 houses, but if your house is set on special soil conditions, it may have some special directions that need followed to protect your home.   

Buying an Existing Home or Already Living There?

It is also important to know these things for an existing home.  I don't recommend rushing out and spending thousands on soils studies and boring samples if you are already living there or just shopping for a new home.  However, become as knowledgeable as you can.  You are or will be the "Manager" of the home responsible for it's care and maintenance, so you need to understand some of its complexities.  You should also try to get at least somewhat educated by your home inspector and/or inspection report, as to how things work, what maintenance needs done regularly.  

So before you spend money especially if you are already there I would recommend the following:

• Look for signs listed above.
• Ask your neighbors, friends that have lived in the area a long time and maybe heard stories of people having trouble with their homes.  Where did they live? etc.
• Check with your government authorities.  City, County, State and Federal.  They have tons of data.  It covers a good baseline and definition for the general area, but don't rely on just this.  "Hidden Dangers" can lurk below.  For example if there was an old drainage - natural or man-made that has been improperly filled in without a drainage system, that fill area will continue to carry the same water it did before it was filled.  This could cause problems either by erosion, compression or swelling. 

• Google it for that matter.    Google:  Soil Types Areas and Maps in Montrose Colorado 

Then unless your comfortable that you have no problem, Hire the Professional.

Are you thinking?  "Oh come on, how could little water hurt my foundation?  Think again.  

Think of a hydrolic jack.  You cannot compress water.  So in clay soils that are more plate like, the water is attracted to and gets im-between the plates and causes them to swell or expand, then when it drys out they shrink again.  Natural Nano-technology that we don't want.

Still don't want to get the professional!  Do more of your own research till you convince yourself that you are willing to risk hundreds of thousands of your dollars on YOUR judgment.

Resources for Colorado and the Montrose, Telluride, Ouray, Olathe, Delta Areas:

http://soils.usda.gov/survey/online_surveys/colorado/

http://soildatamart.nrcs.usda.gov/Manuscripts/CO675/0/WSS-San%20Miguel.pdf

http://soildatamart.nrcs.usda.gov/Manuscripts/CO676/0/uncompahgre.pdf

 

Realtors - Listing or Selling a Home

What if it where your home?

• For most homeowners a home is the biggest investment they will ever make, your fiduciary duty is to help them get the best deal on their investment, this includes avoiding uneccessary risks.
• The foundation is the most critical part of this investment. 
• The dirt or soil that foundation sits on is critical to the foundation.

So whether you want to be a geologist, love dirt or rocks or you hate them.  You need to know enough to advise your clients to seek out expert help, especially if you see or know of a problem that might exist.

If you know you are listing a home in a "bad soils" area or that the Sellers has had problems,  then suggest to the homeowner that if they don't have engineering information and soils reports, that they may want to essentially "pre-inspect" and supply this to the buyer.  If there is damage, it similarly may be worth the investment of having a professional inspect and recommend repairs even if they haven't been completed.

Obviously many of the same potential risks could be here as they are with a seller paying for inspections, appraisals, etc.  Some fear the "professional" will be swayed by the person paying them.  This logic makes sense to me, but I haven't witnessed its abuses first hand. 

I think most professionals are professional!  But throw a couple lawsuit happy lawyers in the mix and that perception could change in a hurry.  So if you provide these seller paid inspections or reports make sure there is a disclaimer that the buyer should investigate themselves and they are being provided as a courtesy.

Similarly for buyers, if you suspect something suspicious or know the area is at high risk of water table problems or foundation problems, mold problems.  You need to make your buyer aware and at least let them decide if they want to spend the money to further investigate.  That is our job.

 

Who are the Professionals?

Realtors - of course but here we need to be professional and tell people they should hire more professionals.

Structural Engineers - They make sure it stands up. They are very smart people. They can do all that complex math and physics calculations to determine live and dead loads of the structure and how they will be distributed to the soil and if they know rather than guess the soils bearing capacity, then they can design the "proper" foundation.  They can also help you figure out how to best fix your home to make sure the money you are spending doesn't go to waste and have to be repeated.  They need to factor in building weight, snow load, wind load, occupancy load, etc.

Soil's Engineers - Geologists - Geotechnical Engineers - These guys are very smart too, but since they love rocks and people say "dumb as rocks" you would think it wouldn't be that hard.  But as it relates to your house they have to understand both physical and chemical properties of the soils and the interaction with the environment (typically water is the key problem, variable or component of change.)

Civil Engineers - Design infrastructure - to some extent foundations, but typically storm drains, surface drainage, dams, roads, utilities, site layout, etc.

Architects - They make it look good and draw pretty pictures - understand quite a bit about Structural but largely are more about functional, practical and efficient space.  Aesthetics and flow.  And they like to party!

Interior Designers - Can sometimes do the work of an Architect and draw plans, depending on their background, typically though they are used for "interior design" how should the kitchen cabinets be laid out, what surface will look right and yet maintain its function.   What floor coverings?  What Finishes?  Color Selection and Coordination. 

Lawyers - Keep everyone honest under the threat that if they decieve or cheat or harm, they will be sued.  Seriously though, in the real estate transactions they typically try to ensure the client is protected from a legal perspective and that all the i's are dotted and the t's are crossed.

Accountants/Book-keepers - Tell us if we can afford to hire the other professionals, and track all the home interest deductions, help us figure out tax credits or special rules.

 

Today we had a Professional Visit our Staff meeting - guess what she talked about!

This morning at our weekly staff meeting we were visited by a local geologist from a local full service environmental and engineering firm (Buckhorn Geotech in Montrose Colorado). 

http://www.buckhorngeo.com

She was discussing our situation and our varied soils in the area.  As a very general rule there are different types in different areas.   In reality, each home site where the home will sit should have a soils test to be sure there is no anomoly.  (e.g. here there used to be old drainages, they were filled in and built over... this isn't a good thing cause the water still goes through there).

I usually tell clients everything to the East of the River is Adobe Clay Soils and everything to the West of the River (the Uncompahgre River) is usually more gravel type soils and Alluvial deposits.  She agreed that as a general rule of thumb this was accurate, because the river has moved east and left these alluvial gravel deposits on top of the shale where spring creek mesa and behind sunset mesa lie.

But what I learned new today is that even where there are the gravel areas, there is shale below this.  Shale turns to adobe clay soils when exposed to the elements.  It also once wet swells and "holds" water or keeps it from soaking in and draining - rather the water moves horizontally along the top of the Shale layer till it can find a crack to escape out of or it just saturates the soil above it.   If this shale is causing a high water table then a septic system must be engineered to avoid ground water contamination.

The shale was under an ocean at one point she explained and the sandstone layers were basically beaches at one point.

And what I was raised to call the Hog Back to the West of the City of Montrose, is not a hog back at all, but truly a mesa.  So it makes more sense to me now that they renamed the "hog back" to "Sunset Mesa" and that it is.

Our desert Mountain Valley is in the center of two uplifting plates.  Most of the ground to the West of the river has in fact had the shale eroded away and or had river deposits placed on top as the valley was eroded and the river was pushed to the east as the plate on the Uncompahgre Plateau rose.

I hope I got all that right.  My geologist buddys would probably rip it apart.

As it relates to Real Estate in the Montrose Colorado area or anywhere for that matter is that if you are buying an existing home or building a new one, it is important to know what kind of soil is under your foundation.  Are there any special hazards or risks associated with that soil.

Many of the Developed soils in the Colorado area present expansive problems.  What this really means is that when the soils gets wet it swells.   Then when it drys back out it shrinks.  It is this movement that affects or can damage a home if not properly managed or designed.

Our guest also explained that some of our soils can also be compressive or not hold up under load and sink or slide.  The cause of this is essentially, that the clays are electrically attracted to water, so the water can leach the clays from the soils leaving voids in some areas.  This is essentially a "sink hole".  As water flows through the soil it takes the clay with it and then leaves a void.   These voids grow over time and can present real dangerous holes under the surface that can collapse when loaded.

You are probably all saying Too Much Information...  Needless to say, I took most of what she told us and regurgitated it with what I already knew and wrote this blog.  

 

May the foundation of your house and your life be SOLID and ON SOLID FOOTING!

Have a great day!    Chris