Please educate me on expansive soils (Denver, Aurora: insurance, house, inspection)

[thatgirl0206]

I've lived in CO for 2.5 years now. I've been reading up on expansive soils. I've watched a youtube video from the Colorado Geological Survey, I've read various online articles and read some threads on here. I still have some questions though.

1- Are there areas of the Denver metro that are not affected by expansive soils?
2- If a house was built 20-30 years ago and has not had trouble with expansive soils does that mean it's unlikely it will have problems with the soil (i.e. do problems show up pretty quickly or they can happen at anytime)?
3- If a house had problems with expansive soils and it was corrected, can it still happen again?
4- If the soil on the property was tested when the house was built and it did not require the special foundation, could the soil become expansive at a later time or is that unlikely to change?

Is there anything else you think I should know about expansive soils?

Thank you!

[thatgirl0206]

I forgot another question I have: For those of you who have dealt with problems from expansive soils, did your homeowners policy cover it?

[davidv]

Answers in red.

Originally Posted by thatgirl0206

I've lived in CO for 2.5 years now. I've been reading up on expansive soils. I've watched a youtube video from the Colorado Geological Survey, I've read various online articles and read some threads on here. I still have some questions though.

1- Are there areas of the Denver metro that are not affected by expansive soils?
Most areas have some expansive soils. It is more common near the foothills.

2- If a house was built 20-30 years ago and has not had trouble with expansive soils does that mean it's unlikely it will have problems with the soil (i.e. do problems show up pretty quickly or they can happen at anytime)?
Soil expansion is caused by water. Some clay soils expand once they are exposed to water. If you have expansive soils near your foundation, it is very likely that is will be exposed to water right away and expand, showing a problem in the first few years. However, if the drainage near your house changes, water that previously had been drained away from the house could get inundated with water for the first time causing a problem after several years of no problems.

3- If a house had problems with expansive soils and it was corrected, can it still happen again?
Correction usually means that the soil is removed and replaces, so it shouldn't happen again unless someone did a half*** job.

4- If the soil on the property was tested when the house was built and it did not require the special foundation, could the soil become expansive at a later time or is that unlikely to change?
The soil never changes, it is just a matter of if the soil was detected at the time of testing. Some subdivisions had a few tests per subdivision. Newer subdivisions have one soil test per lot. If you are worried, check for subtle signs like a heaving patio, driveway or walkway, or maybe cracks in the basement walls.

Is there anything else you think I should know about expansive soils?

Thank you!

[froglipz]

Here you go: Expansive Soil | Basement & Foundation Problems | GEOLOGY.com

[davebarnes]

Originally Posted by thatgirl0206

For those of you who have dealt with problems from expansive soils, did your homeowners policy cover it?

Nope.
The builder's policy did.
Medema Homes did a BK and their insurance company got to replace 400: basement floors, patios, driveways, garage floors and sidewalks.

[DougStark]

I owned an older house in Aurora 20 years ago with expansive soil problems. The doors were out of alignment, the basement flooring sloped. I HATED it.

[kevin_in_Denver]

"However, if the drainage near your house changes..."

Several changes happen after a home is built even if it looks perfect on Day One:

1. The backfill is supposed to be compacted thoroughly, and sloped to drain away. This rarely happens in practice, because it's a difficult job to do perfectly. So the soil (or even the sidewalks adjacent to the house) continues to settle, often causing a negative slope next to the house.

3. If the gutters and downspouts are perfect on Day One, they will still collect rainwater and send it far enough away from the house to prevent problems.

4. On the average house built in the last 30 years, the gutters and downspouts are too fragile to continue to do this important job. They need inspection and cleaning at least twice a year. The downspout extensions are the first thing to get ruined, and sometimes they are the only thing protecting your foundation.

5. The trees near the house grow tall enough to deposit leaves in the gutters, which clog them up. A clogged gutter is worse than no gutters at all, because it will deposit all the water from the roof in one spot right next to the foundation.

6. Gutters are usually assembled with pointy screws. These sharp screws catch the leaves and cause clogging. So always ask for pop rivets in place of self drilling screws. Always ask for the next largest size gutters and downspouts. That reduces (but doesn't eliminate) the chance of clogging.

7. Drainage problems can also cause foundation trouble even if there is no expansive soil. Excess water at one corner of the house will cause that corner to settle more than the rest of the house, which causes trouble. The reason is that although moist soil can support the weight of a house, mud cannot.

8. As your shingles age, they deposit a type of mud in the gutter. This can also clog them up.

9. I swear to God, I have not seen any sort of "gutter helmet" design that actually works long term.

[eatsDEN]

Also, what the neighbors up the street do can impact your lot drainage/water accumulation...

[DavidBilly]

one of the worst areas in town(for exp soil) is S. Simms around Chatfield/Ken Caryl, etc.

[thatgirl0206]

Thanks everyone! This is good stuff for me to know.