Soil Testing for digging out a basement

1/26/2016 at 10:06:27 AM

Hi Lila,

If the company you hired to do the blueprints is stating that soil testing for your property is required, it must be a requirement, in order to get the permit, in the city you live in. You can easily call your local building department, and find out if they need the soil testing to issue the permit.

I do not know if you think that the quoted amount for the testing, seems unfair or too high, but again, you can call testing companies in your area and ask them to give you a quote. This way you will be able to compare prices and hire the company that best suits you.

With regards to the City having soil information for your property, due to the age of your house, it is very unlikely that they will have such information. Also the city, will for sure, require soil testing that will provide current data for the present conditions of your specific property.

I believe that spending some additional money to ensure that the soil conditions of your property are the correct ones, it is worth every penny, to protect your overall investment of lowering your basement.

I wish the best in your project.

Lisandro Donan

L.P.Donan Construction

1/28/2016 at 3:07:01 PM

Hi,

I am assuming that you are are referring to the Geotech testing. I can't stress enough the importance of Geotech testing. Depending how deep they will dig a good test will save a lot of money (as it did to me) because it gives you not only infos about the soil but more importantly about what is beneath the first 4-5 feet of compacted soil. On a 90 years old lot the soil is very compacted however a stick testing (surface testing) that the city inspection requires by law is not enough, too me at least. I have attached some pics so you know what I am referring to. I did this addition the stick testing was normal however after I did the geotech I realized that 2/3 of the footing was on perfectly compacted soil and the 1/3 on very soft soil which was starting to get softer and softer after 6' feet of fully compacted soil on the top. I ended up putting helical piers almost 20 feet in the ground. I would have not done the testing as a contractor it would have been a disaster. Because as you can see the addition was quite big. However your contractor not your drafter should take care of that. You can have the plans drafted for normal conditions of the soil. Once you decided on the contractor and get ready to start the work, you/he can do the testing (as in my case) and if abnormal conditions appears the soil engineer along with a structural engineer (not the drafter) will calculate de loads and the corresponding reinforcement or piers that you will need. Regarding the price your contractor should know some reliable firms already and can give you several quotes.

I hope this helps. All the best with your project.

Paul

Atria Construction