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wanwalker
Member
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# Posted: 8 Sep 2023 11:43pm
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Hi,
I’m new to this forum. I wish I had found this forum earlier.
I bought a waterfront cottage few years ago. It’s built on a steep slope with rocks as foundation. The foundation slides down. Some spots slide big and some spots small as you can see in the photos. I can only think to build a retaining wall to stop it from further sliding. No contractor wants to do the job due to almost no way to use machinery. I decided to do it myself. Is there any easy way for me to do myself? Any suggestion is much appreciated!
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DaveBell
Moderator
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# Posted: 9 Sep 2023 01:13am
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I hope someone piled that rock there and it's not a natural rock formation. Get a foundation contractor onboard to see how high the bottom of the house has to be. Maybe four feet. Jack it up and place on cribbing. 4x4's or 6x6's. Cribbing should not be under perimeter. Google house moving to see how they place the cribbing. You may have to disconnect all the utilities and deck. Rent an electric jack hammer and clear all the rock. You may need a temporary exterior power outlet. Looks like you could just push the rocks downhill. Dig a perimeter trench to pour a six inch deep footing with rebar and concrete. Then built a cinder block foundation including rebar. A contractor will do this part. You need an entry point to get under the house, on the side. Ask the foundation contractor how to attach house to foundation. Jack up the house, remove cribbing, lower house and attach house to foundation.
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ICC
Member
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# Posted: 9 Sep 2023 12:50pm - Edited by: ICC
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I don't have any good news. I do not believe there is a simple or inexpensive solution to this. Nor do I believe there is a good DIY option. Not saying it is impossible, but it will be expensive if done in a safe manner that will prevent future slippage.
Is all that rubble natural or added? It almost appears to have been dumped there. Does it extend along the area? If the rock is natural it appears to be decaying or crumbling. Some rock does that naturally.
I imagine the lake is to the left side of the images?
In my edited image, if the concrete block (circled in blue) that is on its side is supporting the structure it has been placed in the incorrect orientation. On its side like that it is weak and ready to fail. The haphazard arrangement of supports (red circles) is, well, haphazard, no plan. That raises the question of how was the floor assembly constructed in the first place, not to mention other structural elements that are now hidden in walls or under the roofing.
The trees in the upper left of the images are an indicator the ground is moving downhill. We call that soil creep. The one tree (with the red curved line I drew on it) is an especially good indicator of soil creep that has been ongoing for years. The curve of the trunk at the base is the giveaway. That is often referred to as a J-trunk or J-tree. The tree wants to grow vertically and it does its best to do so. Trees with the pronounced but straighter lean to the down slope direction is often an indicator that the clump moved more recently.
It is my belief that more than a simple retaining wall a few inches into the soil is needed. Retaining walls require a very broad base and/or anchoring of members horizontally placed into the slope if they are to actually prevent soil and rock movement That is more easily done before the structure is built.
Looking at the image with the red lined J-trunk tree, am I right to assume what looks like a deck or porch out back is a true vertical (blue arrow drawn)?
Is the property large enough to have another site where a proper foundation could be made and a new cabin built? Re-use some materials salvaged from the present structure? Also what rules are in place with regards to repairs and new construction? Waterfronts often come with an assortment of restrictions.
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gcrank1
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# Posted: 9 Sep 2023 04:46pm
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No, no easy way, no cheap way.
What are the dimensions of the main structure and any add-ons? (ie, porch, deck, etc)
Are there beams under the floor joists and which way do they run in regards to the downhill slope?
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Brettny
Member
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# Posted: 9 Sep 2023 05:31pm
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That looks terrible. Dis you get any type of inspection before you bought it?
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ICC
Member
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# Posted: 9 Sep 2023 05:35pm
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... and where is this? What climate? What is frost depth? Rainfall/snow?
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wanwalker
Member
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# Posted: 9 Sep 2023 06:26pm
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thank you very, DaveBell! I will definite try your suggestion.
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wanwalker
Member
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# Posted: 9 Sep 2023 07:12pm
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ICC
Quoting: ICC Is all that rubble natural or added? It almost appears to have been dumped there. Does it extend along the area? If the rock is natural it appears to be decaying or crumbling. Some rock does that naturally.
It's not nature. I believe the previous owner did some fixes more than 10 years ago before he suffered dementia. There are similar rocks behind the cabin and there is bluff higher than the cabin's roof and I believe those rocks were from the bluff.
some of the random supports were there when I bought it; some of them on the boards were added by me attempting to distribute the weight. you might see couple jacks there. The block is almost doing nothing. The floor on top of those supports was an expansion from the original cabin many year ago. the cabin was built in 1950.
You are 100% correct that the blue arrow is a small deck loosen from the cabin already and that there is >30 degree slop down to the water from the tree. to the left of the rocks there is 6-7' flat area where I'm thinking to build a 23' long 3' X 3' retaining wall. there a 2' slop between the rocks and the flat area. I was standing on the stairs when I took the photos. the other half of the cabin is behind me with a big deck.
I can build a new cabin on top of the bluff. I'd like to keep this cabin as it's close to the water. I believe that rebuilding is not allowed but repairing. Very much appreciated your writing! And all your assumptions were correct. You are the best.
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wanwalker
Member
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# Posted: 9 Sep 2023 07:23pm
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Quoting: gcrank1 What are the dimensions of the main structure and any add-ons? (ie, porch, deck, etc)
The main structure is ~45' X ~16'. there is deck behind me attached to the main structure. The beams run cross the rock line. that the floor along the wall in the photo is lower due to sliding.
Thank you very much!
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wanwalker
Member
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# Posted: 9 Sep 2023 07:31pm - Edited by: wanwalker
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Quoting: ICC .. and where is this? What climate? What is frost depth? Rainfall/snow?
it's 200Km north east of Toronto. it has lots snows in the winter and the frost depth >3'. the building code requires min 4'. In my case, it will hit bedrock before reaching 4'.
Thank you very much!
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wanwalker
Member
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# Posted: 9 Sep 2023 07:34pm
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Quoting: Brettny That looks terrible. Dis you get any type of inspection before you bought it?
not before the purchase. I hired two inspectors after and they had totally opposite opinion on the foundation.
thank you very much!
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wanwalker
Member
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# Posted: 9 Sep 2023 07:38pm
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Quoting: DaveBell You need an entry point to get under the house, on the side. Ask the foundation contractor how to attach house to foundation. Jack up the house, remove cribbing, lower house and attach house to foundation.
this is the ideal approach but it'd be a big project. I did ask a contractor who is doing house raise to take a look and no words back after
Thank you very much!
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gcrank1
Member
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# Posted: 9 Sep 2023 08:16pm
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I was so hoping it wasnt that big....
If it was 16x 20-24 I think it might be manageable, but not 45ish.
My thoughts ran to running suntantial beams, maybe even steel i-beams from down-slope to up, with the beams on bedrock and/or poured concrete pads at the upside and proper piers at the front.
I fear the time and expense may well exceed the value of saving the structure.
Fwiw, around here when similar lake cottages go bad they are often left as just poor lakeside storage and a new cottage built.
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wanwalker
Member
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# Posted: 9 Sep 2023 09:00pm
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Quoting: gcrank1 My thoughts ran to running suntantial beams, maybe even steel i-beams from down-slope to up, with the beams on bedrock and/or poured concrete pads at the upside and proper piers at the front.
It is a good idea. The cottage was done in multiple sections in multiple times. The portion in the photo is a 16’ X 6’ and attached washroom on the far end. The rest of the foundation seems ok. I will measure it and have drawing next week. Thank you very much!
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spencerin
Member
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# Posted: 10 Sep 2023 10:18am - Edited by: spencerin
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So, is the only truly affected section the 16'x 6' addition then? If so, this may have gotten a lot easier and/or less expensive for you.....
If so, how is that addition "behaving"? Just a slight downward slope to the floor? Or, something more serious like pulling away from the larger building?
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wanwalker
Member
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# Posted: 10 Sep 2023 11:17am
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Quoting: spencerin Just a slight downward slope to the floor? Or, something more serious like pulling away from the larger building
Thank you!
One of the inspectors told me it’s like that for more than 10 years. The floor at the edge was 2 inches lower than the middle. It’s level beyond the middle. I didn’t see pulling away from the larger building. However when trying to raise the wall in the photo to level the floor, the middle of the floor raised as well and I can see the supports in the middle loosening so I stopped. I didn’t want put all weight on the edge. Let it settle down a bit.
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spencerin
Member
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# Posted: 10 Sep 2023 10:24pm
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The wood is "frozen" in place, so it makes sense that the middle/joint would rise up when raising the edge up.
A 2" drop across 6' isn't that much. Try raising it in small increments (1/4", 1/2"?) several months at a time. Slowly work it back to level.....
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wanwalker
Member
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# Posted: 10 Sep 2023 11:15pm
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Quoting: spencerin Slowly work it back to level.....
This is what I’m hoping for. Thanks!
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