Are there any precautions I should take if I plan on storing something very heavy near my foundation?

Question

I'm considering getting an ~300 gallon (~1100 litre) intermediate bulk container (IBC) tote to use as a rain barrel, which at 8 lbs per gallon (1 kg per litre; 2500 lbs / 1100 kg total) can get quite heavy when full. I would need to store this near my foundation in order to collect water from my downspouts -- Is there any precautions I could/should take to avoid foundation damage? I suspect I'll need to contact a foundation company/engineer to get the "real" answer, but before I start with that I figured I'd start with the internet first.

Answer 1

No. People park work trucks and hot tubs against their houses all the time. Unless you have a preexisting foundation problem, extreme rain events, a severe slope, or other obvious risk factors, don't worry about it.

Answer 2

There are specifications for load-bearing pressures of foundation materials.

International Building Code gives values between 1500 to 12000 lbs/ft² (7300 to 59000 kg/m²). Lowest for clay or sand, highest for bedrock.

A 3 feet (9 dm) high water tank is 190 lbs/ft² (930 kg/m²), so you are well below even the lowest limits.

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The above values address the situation where the soil would start to shift due to the load, which wouldn't immediately affect the foundation but would be a long-term issue with e.g. drainage and any underground pipes.

In the comments a concern was raised that if the foundation wall was exceptionally weak, the horizontal forces from increased ground pressure could still affect it. Basically meaning that the wall would be weaker than the soil.

We can further compare this to the live loads table which gives design surface pressure of 100 lbs/ft² for "Yards and terraces, pedestrian" and 250 lbs/ft² for "Sidewalks, vehicular driveways and yards, subject to trucking". No margin here, though these are the minimum design limits which would typically be exceeded by a lot if there is no hollow structure underneath the yard.

I agree that the topic is more complex than what my initial answer presented. To properly calculate lateral earth pressure due to the surcharge load would require quite detailed analysis.