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aroden15
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# Posted: 8 Mar 2023 06:46am
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I recently finished clearing my land here in Texas, and we are excited to get building. I have had a few dirt work guys comes out to quote me for a building pad and other dirt work. I was debating between a pad and putting an 18x52 cabin on blocks or placing 6x6 posts in the grond/pad. Due to being on a fairly steep incline one of the guys suggested that i just pour some concrete piers and then build off of those. This could potentially save a lot of money on the dirt needed to be brought in. This is where I really need some help as I am new to this. The soil is really sandy and I have no idea how to figure out the pier sizing and spacing. I can give all details of cabin size if needed. Any help would be greatly appreciated.
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gcrank1
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# Posted: 8 Mar 2023 10:01am
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18x52 is a substantial building (and such get Heavy really fast) too much for on blocks and on a slope Im pretty sure the kind of piers needed are not going to be simple or cheap. Fairly regularly we have folks join and post up pics of older cabins on 'shifting/failing' piers on a slope. We think of the ground as being firm and stable but ime it is 'always moving downhill'.
Considering the work and expense of the structure are you sure you want to try to scrimp on the foundation?
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Tim_Ohio
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# Posted: 8 Mar 2023 10:59am
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My opinion is that yes, you can use piers. Appropriate number, size and depth of the piers will achieve cost savings and be structurally sound. Look at all of those beach houses that are elevated on treated columns.
Anyway, my biggest concern would be drainage. Anytime anyone builds on a hill side, there is going to be a lot of water movement. I'd have a very nice drainage swale excavated behind the structure and graded down from the center or one side to the other to direct surface water away from the structure. The last thing you want is for the hill side to wash out and have the structure go with it. This would be my biggest concern.
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Brettny
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# Posted: 8 Mar 2023 12:03pm
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Quoting: Tim_Ohio I'd have a very nice drainage swale excavated behind the structure and graded down from the center or one side to the other to direct surface water away from the structure.
Do this. Site prep is overlooked way to much and can be very very costly after a building has suffered the effects of poor site prep.
Site prep dosnt always mean getting a level pad built. It can mean removing large trees, drainage and other things that cause major issues in the future.
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Steve_S
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# Posted: 8 Mar 2023 12:37pm
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My own place is on top of a 1700 foot where 3 valleys meet up. The entire region is forested, generally it is mixed but mostly cedars & pines with a bit of everything else sprinkled in. The soil here is Sandy Loam and is about 8-10' deep on average with Banded Granite as the bedrock.
I built my place on a Frost Protected Slab Foundation, so we excavated the Sandy Loam from my building pad, back filled & packed in Pit Run Gravel and then topped that with fine crush which was then again compacted by the 35 Ton excavator.
While the soil is generally stable, I am on a downslope and like all things in nature, things shift over time. I chose this route as it provides a very solid base (goes to bedrock) and will not shift (not in my lifetime anyways). As part of the PAD Prep. we also installed a French Drain on the high side to manage any water (rain & snow melt) and to direct it downsloap and away from my structures. I have to say, that French Drain flows a LOT of water starting March through to end of April... I go down to the end and the water is just gushing out the hillside where the drain is. FYI: At present I have 3m/9.8' tall Snowbanks all around my house & down the driveway, so snow melt is a real thing up here and holy macaroni it can get really bad & fast.
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curious
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# Posted: 8 Mar 2023 05:39pm - Edited by: curious
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Comparing a beach home constructed on a pile foundation to a cabin built on typical piers as seen for many cabins here is akin to comparing a Kenworth to an F150.
Piles used for beach construction are driven into the soil, not placed in dug or drilled holes. They are driven as deep as 16 to 30 feet depending on the soil/sand conditions. No comparison.
Yes, soil drainage is a big factor in having a long-lived sturdy structure. Texas has a variety of soils and many have problems. I would consult a good foundation company or an engineer with familiarity with the area. Note that Texas also has a great many foundation contractors who specialize in foundation repairs. That should tell you something.
An 18 x 52 structure is a house, not a cabin. As such it deserves a real foundation
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aroden15
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# Posted: 9 Mar 2023 06:39am
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Yes, i realize 18x52 is a pretty good sized structure, but that is also why I am trying to do it correctly. There are cabins of this size going all over with just blocks, burried 6x6's, poured piers, slab foundations etc. I appreciate all the responses, and will take them all into consideration. I have no experience in actual foundation so that is why I am glad I found this site to ask people with more experience.
As for drainage, we have a very good plan. Everything will be formed so that it drains from up top and around each side of the cabin. This will prevent any washout under the structure.
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gcrank1
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# Posted: 9 Mar 2023 10:21am
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A good way to start may be to find what the local building code calls for.
What, no code/no requirements? No problem. Find out what is required in a place close by that does have a building code.
Fwiw, Ive never seen a building that didnt get more complex and heavier than planned initially.
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jsahara24
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# Posted: 9 Mar 2023 11:02am
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If you are going with piers I would use some type of spread footer for a structure that large. Bigfoots are common but there are other options as well.
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Grizzlyman
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# Posted: 9 Mar 2023 06:32pm - Edited by: Grizzlyman
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I don’t see why you can’t use post/beam construction. . Many of us have cabins wider than 18’ on posts/sonotubes. You can make it as long as you want and the loads will be the same per post for an 18’ wide building whether it’s 20’ long or 100’ long. You’re gonna need a ton of em… but it’s doable.
18’ wide you’ll need a central post as well as two outer posts. Spaced at 8’ the long way you’ll need 8 x3 wide= 24 posts.
6x6 posts and sonotubes should work well. Cross-bracing is key.
Or depending on how high above the ground anduneven your terrain is, you could pour the sonotubes level and put the beam right on that… though is suspect that would be difficult to do.
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