• Welcome to The Building Code Forum

    Your premier resource for building code knowledge.

    This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.

    Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.

    Ready to upgrade? Log in and upgrade now.

What to do with less than 4' of frost protection?

R

RyanBuilder

REGISTERED
Joined
Apr 9, 2018
Messages
11
Location
New Hampshire
Hello all, I'm building a home in Massachusetts near the ocean. We have a walkout basement on one side and I needed to step the trench down for frost protection under the door. The soil is terrible, all hard clay and we dug to right above the water line for the rest of the footings. The step down trench is full of water and this project has a conservation order of conditions which says we cannot dewater. Since it would have been impossible to pour without dewatering, the engineer came up with a plan to construct a dewatering trench to pump the water to, which we dug and laid out last week.

Planning to pour yesterday, I showed up and the step down trench was full of water so I turned the pump on. Then I checked on the dewatering trench and it was filled to brim with water. There is no place to put it!

My thought is to fill in the step down trench where we need the frost projection with stone, but that will only leave us 2' below grade. How can I properly insulate this with rigid foam? It seems like this is my only option since we can't get rid of the water. I've never had to do this before. Thanks in advance!
 
Welcome

Give it a day or so and you should get some answers

Can you pump the water into a holding tank???

Sump pump or similar running all the time?

Or pump it early in the morning and pour later that afternoon??
 
In our climate, we use 1" of foam for each foot of frost cover needed. The foam needs to extend both out from the footing and up the wall for at least the missing amount of frost cover. We require 4' of cover, so in your situation, we would require 2" of extruded polystyrene to extend 2' out and 2' up the wall. This is highly dependent on climate, so you might want to speak with a local expert, such as an engineer.
 
Thanks tmurray.... I would have 2" of foam running vertically up the footing, then a short horizontal piece on top of the footing to where it meets the wall, and then a piece vertically up the wall to grade? and then a piece horizontally extending 2' out from the bottom of the footing? Is there a way to attach the foam?
 
After reading this again, I'm thinking the vertical will meet the horizontal at the top of the footing and the footing will be below the foam?
 
Check the 403.3 frost proof foundation require the building to be heated to 64 deg year round.
second with that much water I would be very carful of freezing soil.

you may have to rent a storage tank for the water if you cannot find way to discharged it on the site
 
you would have on running vertically up the wall and one extending over top of the footing and perimeter drain (draintile). You have to think about to keep the underside of the footing from freezing. There needs to be the equivalent of 4' in every direction (except inside the house).
 
Design the building based on the site rather than adapting the site for the building.
Elevate the building and use caissons.
 
You must log in or register to reply here.
Back
Top