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tonymsn
adding basement approach

How would I add a basement to our crawlspace without jacking up the existing building? I plan on using 8 inch concrete wall. The House is D-log single story.

Re: adding basement approach

It needs to be underpinned and it's demanding work that needs to be done correctly.
I would consult with a professional engineer or architect.

canuk
Re: adding basement approach
tonymsn wrote:

How would I add a basement to our crawlspace without jacking up the existing building? I plan on using 8 inch concrete wall. The House is D-log single story.

Let's put it this way --- you want to remove the existing foundation that currently supports the house -- excavate underneath --- pour a new foundation.
Somehow the house will need to be supported while all this is being done -- as well the house will need to be raised somewhat to allow the concrete to be poured into the forms.

Doing some preliminary homework will put things in perspective as to what's involved and the feasibility of the project.

Your first stage of planning should be consulting with the local municipal building department on what you wish to do. They will advise you all the requirements needed --- including permits.

Also , consider utilities like sewer , water , natural gas ( if available ) will likely be disconnected while construction is underway. There's a likelihood you may be forced to live elsewhere since the utilities will be disconnected and the fact the house will be temporally supported.

Next in the planning stage is to source out a foundation contractor experienced with this type of retrofit and have them visit the site to give you a ball park estimate. This is just for getting some numbers to work with.

The reason you want a contractor experienced with retrofits like this --- it's different to digging out a hole and pouring the foundation on an empty lot compared to excavating and pouring a foundation under an existing building.

With an empty lot --- an excavator comes in with a backhoe and digs the hole --- a crew shows up to form and pour the footings --- later they come back to setup the wall forms and pour in the concrete --- fairly straight forward and relatively quick.

In your case there's a building in place. This means after the building is supported they need to somehow excavate underneath. Depending on site conditions and accessibility will determine how that's done and will impact the price. If site conditions are favourable the excavation maybe done with a small skid steer and minor hand digging. Otherwise, if site conditions are tight the excavating may require hand digging which is labour intensive and slow.

Of course you also need to consider what will be done with all that dirt from the excavation.

Next , contact a structural engineer to inquire the cost of their services to design and provide certified drawings of the foundation. Again, this is just for getting the numbers together.

If you decide to proceed -- enlist the the service of the engineer to design and provide the certified drawings of the foundation. You will need this to submit to the building department anyway.

Once you have the drawings , have the foundation contractor provide you a quote based on the drawings .

After those are in place then submit your application for the permits --- once approved --- go to it.

2 cents worth.

jkirk
Re: adding basement approach

if you do go ahead with such a project check the builders insurance and certification. do no simply accept "yes we are certified and licensed" 6 years ago in town a women hired a contractor to do the exact same project, this contractor wasnt licensed or insured. they had the house jacked up 1/2 way only for the shoring to fail and the house collapsed. when she tried claiming it through her insurance they told her no because there was no insurance company to get money from to help her, they then cancelled her plan for neglagence.. worst part she had this done in december, and she was without a home a week before christmas

Timothy Miller
Re: adding basement approach

Howdy, "when she tried claiming it through her insurance they told her no because there was no insurance company to get money from to help her, they then cancelled her plan for neglagence.. worst part she had this done in december, and she was without a home a week before christmas "

This is very unusual her homeowners insurance has a contractual obligation to pay for collapse see policy for covered perils... The insurer owes the insured and if they can proof someone other then the insured caused a covered loss then they subrogate to recover her deductible and their money. If they cannot recover then nothing happens further to the insured. The loss history of an insured is reviewed an underwriters make decisions on coverage . Not knowing more then to tell her to contact her states insurance commissioner for assistance. Or spend an hour with an attorney whom handles theses type of issues to review her policy and the formal denial of coverage.....

The post. Sell the house and buy one with a basement much less of a headache.

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