Hello Folks,
A “rookie” question here. Help is appreciated.
I have an important question to ask regarding building a foundation. I am looking at a retirement home being built 3-5 years away in northern NH. My issue is the site I want to build on has about 3-4 feet of topsoil and then ledge. the house would sit up on a rise on the land and give me a spectacular view of a string of Mts. The area on the lot is where I want to build. This way my septic will be downhill from me.
My question is “Can I blast down about 5-6 feet or so and then pour a full foundation or would I be better to pour a slab and “pin it ” to the ledge? I have my heart set of a full basement but don’t want hassles with water. The is a stream nearby (100 ft away) and I would hate to get leaks in the basement. I would want the basement to be water proof. Would tarring the outside of the concrete, along with gravel beds and drainpipe at the fottings be enough or would I have to do more with a ledge involved? Is this possible or unrealistic? Also, could I blast down a foot or so and then build a foundation 4ft underground and then 4 feet above?
Finally, if we are talking about blasting, how much money/time would it take to blast a hole in ledge for a foundation about 45×30?
Should I have my head examined or is this a fairly common type of building problem? Otherwise the land is wonderful.
Thanks in advance for any advice you can provide. It is much appreciated.
Regards,
McMick
Replies
Could add as much as forty thousand or so to cost but certainly doable. It's a pretty good sized building.
better choice tho' might be to pin footings for full foundation on top of the ledge with minimal blasting in and then berm soil up or do a walkout basment on the south side, depending on terrain.
Excellence is its own reward!
I am just in the process of a similar project in the Mt. Sunapee Region. However, bedrock is within 1 foot of the surface. The house is about 25x40 and of course I overblasted the sides 5+ feet and the base was overblasted a couple of feet. The cost was about 6K. However, note that I am on the top of a high hill and have no drainage problem. Also there were no close neighbors to worry about when blasting. The biggest item in your construction is how to drain the foundation - especially in mud season - You will need to put in something like 1 1/2 inch stone around the foundation and with your footing drains (I am using form-a-drain) drain to a spot significantly downhill and away from the septic system. Hove you sited the septic yet? With bedrock etc - my experience was that the septic was the most difficutl and costly.
For waterproofing (nothing is really proof) there are any number of membranes on the market that you can use. My thought was originally to pin but the rough nature of the bedrock combined with frost protection considerations drove me to my solution.
Hi Ron (and Piffin)
Thanks for the replies. That's a significant difference in price 6-40K. Ron how deep did you have to blast and who did you use in NH? I was wondering if they would travel to the Whites.
I am having second thoughts about the property now. I was planning around 300-350 for everything. Just getting the land and foundation set up sounds like I'd be about 150K into that number before I would even start to do a house. I have 6K in a P&S but now am having second thoughts. I don't want to taost all my retirement on a house. I'd rather lose the 6K.
Ledges can be a deal killer......
Thanks,
Michael
Get some one up there to take a look. I used Daniels Blasting - they were near Manchester/Concord. Let me know how you make out. Also you need to make sure that someone takes out the rock. Daniels charged me 6K and it cost another 2K to remove and another 1K to put in the stone (approx. amounts) But the view will be worth it in the end.
Ron
Thanks Ron,
That's who I had recommended to me as well. I believe they are out of New Boston? I'll have to give them a call.
Thanks for the insight. It's a great help for this rookie.
McMick.
here's the diff.
I said "as much as..."
eight grand might do the actuall balsting but there is more to it than just that. You've still got the excavation, re-compacting, drainage, waterproofing, etc. So I'm reporting an outside figure for added cost over crawlspace or slab only with all added costs which is what will be coming out of your pocket to do this.
These other guys are reporting ONLY what the blasting might cost in a best case scenario.
Best advice is get someone on site, but even then, with ledge not exposed to daylight, it's only an educated guess..
Excellence is its own reward!
Good Food for thought. I need to definitely know the overall costs.
What do you (or anyone) think going with concrete footings and have them drillied into the ledge instead of a full basement? I know I would still need drainage and such but with 3 feet of topsoil to clear away , I could still have a little crawl space below. I would think it would be a darn bit cheaper . I would just spread the house out a little more to compensate for the loss of basement. It would be a tradeoff in building costs and more sq ft but I still think cheaper.
I gotta have a workshop somewhere- even the second floor of a garage!
Thanks
McMick
Maybe slight savings in materials but crete on a sloped short ledge is definitely not cheaper than pouring a footing in bank gravel.
Excellence is its own reward!
"Maybe slight savings in materials but crete on a sloped short ledge is definitely not cheaper than pouring a footing in bank gravel"
I agree though it depends on the amount of blasting needed. If you have exposed ledge in your basement you will have water problems, no matter what you do with drainage and sealing the outside of the foundation. Water will find its way though any fissure in the rock. We have had to cover the ledge with wire mesh and cement plaster and provided drainage for the water under this to eliminate the problem. I a large basement this costs thousands of dollars.