Pier & Beam Dock House

Started by Jerry Hambley, May 07, 2005, 05:32:59 PM

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Jerry Hambley

I want to build a small cabin (1 story with loft) next to my pond. The cabin will be 16' x 24' and located right next to my 2 acre pond. I would like to attach a deck to the front of the cabin that will extend out from the cabin to become a dock over the pond. I have purchased John's plans which include a pier and beam foundation diagram. My frost line is apprximately 36".

My question is...should I be concerned about the piers of the dock house being subjected to wet conditions as the soil is very close to the pond. Would it help if I drilled a deeped hole and backfilled with gravel?

Also, any suggestion for the piers in the pond themself? (the pond is already full).

Regards

glenn kangiser

Possibly you could use steel pipe in the pond to make a cassion  to get a dry area and pour concrete inside of it.  

I don't know what your depth of water is or how far to firm soil or how much weight you need to support, but can give you more info if this is of interest to you.

Maybe the others have some ideas also.  How far into the water are you going?  Do you hit water in the footings if you dig down? How deep is the water?  How far is your deck/dock going to be over the water?  How high above the water?  If you give us this information we may be able to suggest more options - and as always, no guarantees.

This may require the help of a local engineer - are you in a permit required area?
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.


jonsey/downunder

#2
How about a floating deck/dock with a flexible bridge from the house.

I've got nothing on today. This is not to say I'm naked. I'm just sans........ Plans.

Jerry Hambley

I haven't dug a pier hole yet so I don't know If I'll hit water on the cabin piers. I'm guessing it will be damp. The water will be about 4'-5' deep at the father edge of the dock. The dock will extend 12' into the pond. I guess I would want to set the dock about 16"-24" above the high water mark.

Building in a rural area so not codes or inspections are required.

Jerry Hambley

jonseyhay,

The floating dock is a possiblity I've been investigating as well. I still have the issue of the piers for the cabin however.

I just don't want the footers to heave in the winter. No real way to drain them being this close to the lake. Just though the gravel base might provide enough expansion area for the water in winter?


Jerry Hambley

What about using this product? They even talk about pouring an underwater pier in their FAQ section

http://69.20.124.116/ABS2_Bigfoot/AbsPage.aspx?siteid=1?=1&id=3

jonsey/downunder

#6
I have put a drawing of a modified version of my stumps on my house page. You may like to look at it, feel free to use it if it's of any use to you. There is a caveat though. I am no engineer so you will need to have it checked by some one who knows. Frost heave is not something I am familiar with. I have not worked in areas that cold; you will get better advice on that from some of the others on the forum.
Link here.
http://users.tpg.com.au/jonsey/house/stumpdrawing.jpg.

I will remove it and the link in a couple of weeks as I am running out of free webspace. It may be of some use to you so help yourself.
jonesy
I've got nothing on today. This is not to say I'm naked. I'm just sans........ Plans.

Jerry Hambley

Thanks for the posted drawing. Let me ask a few questions.

1. I'm guessing that the rod allows the beam to be leveled to start and also in the future?
2. How is the straping attached to the post? Is this strapping the only thing keeping the beam from slipping off of the rod?
3. If the beam needed to be leveled in the future how does the strap need to be adjusted?
4. Is the pier just sitting in the concrete or are there bolts etc that keep it firmly embedded in the concrete?

Sorry for all the questions, I just want to make certain I understand your drawing.

jonsey/downunder

#8
1. I'm guessing that the rod allows the beam to be leveled to start and also in the future?
Yes the pier is adjustable up to about 4" some thread needs to be retained in the tube to stabilize the bearer.

2. How is the strapping attached to the post? Is this strapping the only thing keeping the beam from slipping off of the rod?
The strapping is simply tech screwed to the post in a couple of places on each side.

3. If the beam needed to be leveled in the future how does the strap need to be adjusted?
Just remove the tech screws and replace.

4. Is the pier just sitting in the concrete or are there bolts etc that keep it firmly embedded in the concrete?
The pier is embedded in the concrete you would need to weld some reinforcing to assist this. If you go to my site you will see that I have used a plate set in the concrete and the pier is welded on top.(click on the little house on the left side bar over there
<------

Here is a photo of the store brought system
http://users.tpg.com.au/jonsey/images/stumpaj3.jpg.
I've got nothing on today. This is not to say I'm naked. I'm just sans........ Plans.



jonsey/downunder

No problems Mate, hope it's of some use to you. You may find a search on adjustable steel piers will turn up some useful information. Don't forget, get this all checked out by someone qualified
All the best

I've got nothing on today. This is not to say I'm naked. I'm just sans........ Plans.

glenn kangiser

Do you have both freezing and water level changes to deal with ???  
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

Daddymem

Since you mention frost line, I'm assuming you are in an area where the pond can freeze over?  The dock and deck should be separate from each other. As the pond freezes, it expands and tends to lift docks upward while the house may be standing pat.  Around here, the docks that remain in the water year round and don't have problems float on the water.  The anchor is simply a series of tall posts that the dock slides up and down and back and forth on as water levels, waves, or ice forces make it move.  Stationary docks get warped and twisted eventually.  Assuming this is a natural pond, you will also be subject to differential settling.  The pond area is likely to settle most over time and less settling will occur as you get further from the pond.  Whatever you do, try to get any piers below the frostline so the non-expanding soil can grip the piers and hold them in.  Personally, I would consult someone local who is familiar with your soils and has some experience with what works and doesn't.
Où sont passées toutes nos nuits de rêve?
Aide-moi à les retrouver.
" I'm an engineer Cap'n, not a miracle worker"

http://littlehouseonthesandpit.wordpress.com/

Jerry Hambley

Glenn,

The pond may go lower but the water level will never go higher than the spillway.

I have decided to separate the deck and the dock...making a floating dock.

My main concern are the cabin piers closest to the pond because of the perculation of the water from the pond into the bank during the wet periods of the year and the possible shinkage caused by drought in the summer. I'm in Kansas City, Kansas so we may have periods of time when the pond could possibly shallow freeze but nothing like up further north.


glenn kangiser

I think Daddymem, our off duty professional, said it well.

I think you made a good choice separating them.

My dad's place has been sinking into the ground for 70 years or so.  I would probably check out the ground under the front edge with a posthole digger, quite deep if it were me- see what's under there- see if there is a substantial footing deeper, then decide.  It may be beneficial to try to float the whole thing on a full footing if concrete and rebar are not a problem.  I would design it so there is room yet for something like Jonesy's adjustable stumps or at least to get a jack in to re-level later.

If in doubt as Daddymem says, check what works locally or ask a local engineer to devise a good foundation.  Our advice is suggestions only - we don't accept any responsibility or liability for what you finally decide on, but hope what you get here helps.  Keep us posted on your progress.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

Daddymem

I should point out that I am a site civil engineer, not structural.  Basically I design the layout of a site and the infrastructure but nothing to do with the building itself.  I only do septic systems for single family homes (and usually just tough sites at that), the rest of my work has to do with large buildings with a whole design team from architects to structural engineers so I don't worry about things such as foundation types and soil bear capacities.  Glenn, John and many others here know more about home building than I ever will.  Civil engineers are the "swiss army knives" of engineers, our course work covers many, many topics, but we usually specialize in a few areas only.    Structural, and geotechnical engineers are the ones dealing with building foundations and soils.
Où sont passées toutes nos nuits de rêve?
Aide-moi à les retrouver.
" I'm an engineer Cap'n, not a miracle worker"

http://littlehouseonthesandpit.wordpress.com/

Jerry Hambley