Hello,

I am planning on building a 10x14 boat house at my summer cottage. I will be building it on dry level ground. I am thinking of pouring 6 cement slabs (2 feet sqaure, 1 foot deep) and then buildng the floor (2x8 joists) right on the slabs (anchord), and then building up from there (single story). Any thoughts or suggestions on this?

Thanks

First, let me welcome you to the pool. I am sure you will find a lot of valuable information here. Just remember, we do not know your capabilities or the conditions in which you are working.

I am guessing that NB is New Brunswick, Canada. I think it gets more then a little cold there. My first concern is frost heaving of the cement. One foot is not going to be below the frost line. If you do not have a frost problem, then ignore this post.

If I read your thoughts right, the floor would be a wood deck on the 6 cement pads. I do not believe his will work. One or more pads may be pushed up causing the floor to go out of level and “rack” the building. While 6, 1 foot deep slabs will keep it from blowing away, they won’t be below the frost line. Water under the pads will freeze and push the pads up.

I think I would build this like a deck. Pour 6 or 8 inch column footers, at least 4 feet deep, check local building code for the frost line in your area, then build on that. This is hard for me to predict, but you may run in to rocks or boulders when you drill you footers

There are more learned folks here that can better describe this method.

From a DIY advice site -

I live in New Brunswick , Canada. that means I'll have to dig about 4 feet to ensure I'm below the frost line.

It sounds to me like you need to pay a visit to your local building department. Pouring separate 2' square slabs is a bit of a mystery to me, why would you take that approach? It sounds like perhaps you need some professional local consultation to do this job properly.

What you should do is dig a trench for a proper footing all the way around the perimeter. You could possibly get away with doing footings at the corners only because it's a small structure, but ask yourself if this is a building that you want to last or just something you are going to throw up and watch deteriorate?

If you want it to last then you should put in a proper foundation with anchor bolts tied to the wood framing. You would most likely pour a 4 or 5 inch concrete slab as the most durable and weather resistant approach. Your walls would then be framed on top of the foundation wall and the sill plate would be anchored to the wall using proper anchor bolts.

I highly suggest you go to your local building department though. In some cases they will prevent you from creating a disaster for yourself... as in, if you had gone ahead and built without going below the frost line, your structure would be pretty useless in a couple years time.