DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Building & Construction (
-   -   Adding rooms under cottage (

billybarty 02-19-2008 08:51 AM

Adding rooms under cottage
I have a cottage that is built on a hillside that I want to add a couple of rooms under the front. The back of the cabin is resting on the ground and it slopes down to the front that is about 4 feet off the ground. For supports there are 5 6x6 beams running about 75% to the back of the cabin that are supported by 4x4 treated posts resting on deck blocks.
I want to dig down to about 9 feet starting from the front and go about 13 feet back so I can frame in a couple of rooms for the water tank, etc and a bedroom.
I don't know how I can dig out the dirt and support the cabin at the same time until I can put new supports in.
I was thinking I could start on one side, remove the existing supports, dig down and back as far as I need to and then put some telepost in for support and continue to work this way from one side to the other. I also need to know how to put a floor under this while it's still supported. I thought perhaps once the teleposts were all in place I could pour a concrete floor and leave the teleposts cemented into the floor or should I pour around them?
I hope I've explained what I want to do clearly enough and if anyone has had any experience doing this it would be greatly appreciated. Any advice on pressure treated wood floor or concrete and handling moisture would also be appreciated, it's a heavy clay soil.

Thanks in advance

Ron6519 02-19-2008 09:54 AM

My advice would be to hire someone with experience to do the structural work. You can then do the work that won't compromise the house or your health.

Brik 02-20-2008 08:55 AM

I think you are over your head as far as doing it yourself is concerned. I doubt the complexity and cost of this project would be worth it (Depending on size, location, etc)

My first though is to use a crane or house mover to move the cottage to a properly poured basement just to one side or another. Doing it in place is asking for trouble.

billybarty 02-20-2008 12:37 PM

Thanks for the replies but I would like more constructive advice than to get a professional to do it.

oldfrt 02-20-2008 07:22 PM

Try finding something helpful on this site:

Take note of the cribbing used to support the building for a secure job.

Maybe try some similar sites for hints as to what is within your capabilities.
Above all else ,do it safely!!

I added a second floor to a cottage that was once built on pickel barrels.
The owner(an older German guy)had hand dug for new footings,and built a block foundation (frost wall)for the new crawl area( cellar).

He then built new exterior walls outside the existing framing and
used a bottom plate wide enough to support (and tie together)the old and new exterior walls before he set it on the new foundation.
Using a number of house jacks(on top of cribbing) and steel girders he leveled the cottage before he laid his last courses of block.
It can be done,but not with teleposts.

Don't underestimate the amount of work and knowledge needed here.
The old German was a mason and had worked construction for many years.
If you try to support that building on teleposts,your going to find it toppled over,hopefully without someone under it.

Brik 02-20-2008 07:58 PM

If getting a pro isn't to your liking and moving the cottage onto a proper foundation (next to existing) isn,t an option then I would do cribbing and beams to support the cottage completely. This will then require excavation by hand. Build a proper foundation and lower off the cribbing onto the new foundation. Not simple.

billybarty 02-21-2008 08:07 AM

Thats what I did last year was get it supported well with beams. I don't plan on supporting the place with teleposts, when I'm done it will still be supported by the beams as well as exterior walls, what I'm looking for is a way to dig out the dirt and build the wall while working around the current beams and supports. I can dig it by hand but I'd like to be able to use a skid steer. It is currently supported well and I'm not careless so I don't think i'll get squished

Brik 02-21-2008 09:08 AM

I'm picturing temporary beams extending past the width of the cottage and resting on cribbing that is not under the cottage. Essentially clear the way to do a proper excavation and then construction.

oldfrt 02-21-2008 09:26 AM


Originally Posted by Brik (Post 100011)
I'm picturing temporary beams extending past the width of the cottage and resting on cribbing that is not under the cottage. Essentially clear the way to do a proper excavation and then construction.

:thumbsup: Definitely the best approach,Brik!!!

I wouldn't use the teleposts at all for what you're trying to do.
The height of them alone,would cause enough instability for concern.
If there isn't enough lateral support,the cottage could slide off its existing supports.
Everything has to be lifted(or supported) at the same time.
Your talking 9' of telepost?
There's no way that is , in any way ,a safe approach.

billybarty 03-07-2008 09:04 AM

I never planned on the teleposts being the sole form of support during excavation. I have gotten a 24" power pole that is about 40' long that I am going to put on top of cribbing made out of railway ties that lie outside the boundary of the cabin. The first area I need to support while I pour a footing and build walls is about 25'. Would that size of post be thick enough or should I try to get a steel pipe or beam?

Bondo 03-07-2008 09:12 AM


or should I try to get a steel beam?
That would be My choice.....

billybarty 03-07-2008 10:10 AM

I can get the power pole for free but probably won't be able to borrow or rent a steel beam or pipe, that's why I'm hoping the power pole will enough

Bondo 03-07-2008 11:55 AM

Power Poles will take massive Compression loads,...
Are no better than any ole Tree for side loads.......

The whole idea is you need total free space under the house,....
Supporting the pole at mid-length will defeat it's purpose....

kiwi54 03-07-2008 03:24 PM


Originally Posted by billybarty (Post 99726)
Thanks for the replies but I would like more constructive advice than to get a professional to do it.

Ron gave you the best advise, get a professional to raise the house, there's nothing more constructive than that. I've added poles to homes in New Zealand and have no problems doing the work, BUT, I didn't raise the houses. I had a house moving crew come in, raise the house, crib it on steel beams so that I have clear height and room, do the work and have them lower the home back into place. They have the experience and the right equipment to do it. This is a major task, nothing is free and there's no short cuts.

I had a married couple actually live in the home while it was up there, we gave them temp plumbing and electrics and a 12' high temp set of steps. They got a buzz out of being able to do this, didn't worry me except they were there looking over our shoulders all the time....:wink:

With clear access, no problems laying a pad.

billybarty 03-07-2008 03:49 PM

Maybe I didn't explain it properly, I'm not raising it. It sits on the side of a hill with the back of the house resting on the hill. The front is about 4 feet off the ground. I want to hold up the front so I can dig out underneath to build a room for my utilities. I don't think using ties for cribbing and a good beam under the front is unsafe or too difficult to do.

All times are GMT -5. The time now is 03:28 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1