Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 07-22-2011, 11:08 PM   #1
Member
 
Join Date: May 2011
Location: Massachusetts, USA
Posts: 325
Share |
Default

Pimp my Crawlspace!


I am the bemused owner of a 1941 single-story cottage. Topside it is rather nice and in good shape, but the real mess is the crawlspace. I've attached a picture to give you a sense of the situation.

The house is 18' wide by 32' long. There is a front room that was a former porch that is 18' by 8'. The middle part of the house (bedroom and living room) is 18' by 12', and the back of the house (kitchen and bathroom) is also 18' by 12'. The floor was built in three sections corresponding to the above dimensions. There are two rows of 4' by 4' beam sections running the long way down the house, and 2' by 4' joists butt between them to span the floors (i.e. 6' joist spans). I've attached a quick sketch of the floor arrangement with where the supports need to be.

The "piers" are what you see in the picture - a mish-mash of concrete blocks, old clay sewer pipes filled with concrete just wedged in on top of the sand, etc. No footers of any sort. A lot of the columns and beams in the picture are just jammed in to stiffen the floors (the joists are just toe-nailed into the beams). Some of them aren't even touching the joists, but I can't take them out because of wiring stapled to them.

The crawlspace height goes from about 14" at the shallow end to maybe 3' at the deep end. (yeah, I have my Army crawl technique down pat!) My dream is to clean this up, get some proper support structure installed, lay some plastic down and insulate the floor joists.

I fixed a cracked and leaking sewer pipe a few months ago and the crawlspace is pretty dry. Right now I am just installing joist hangars and pulling wiring off of the beams, trying to get stuff out of the way and trying to figure out what would be the best thing to do.

One thing that I was considering was taking out the old front porch floor at the front of the house (it wasn't well done anyway, and is only 8' by 18'). This would give me access to the crawlspace at the shallow end. Then, instead of pouring individual piers, could we dig two ditches for footings and pour two bearing walls down the length of the house? It might be possible to back a concrete truck up to the front and pour through the front door if I did this.

Does anybody have any experience with shallow crawlspaces like this and different methods of digging, getting concrete structure, etc.. down there?
I am going to pull in a professional to do this as it is beyond my capability, and I would like to have it done properly. But I'd really like to know what sorts of things could be done so I can discuss and plan knowledgeably with the contractor and feel comfortable that they know what they are doing.
Attached Thumbnails
Pimp my Crawlspace!-crawlspace-03062011-037.jpg   Pimp my Crawlspace!-floor-plan.jpg  


Last edited by Thunder Chicken; 07-23-2011 at 01:04 AM. Reason: Name change, added sketch.
Thunder Chicken is offline   Reply With Quote
Old 07-23-2011, 09:15 PM   #2
I ask the impossible!
 
Join Date: Aug 2010
Location: Royal Oak, Michigan
Posts: 1,069
Blog Entries: 7
Default

Pimp my Crawlspace!


If you want to wade through my history of threads started you might be able to learn some stuff, although a very large bulk of my posts has been electrical related. My house is very similar in construction to yours. Mine was built in 1917 and is supported by columns of cement blocks with no proper foundation.

Strictly speaking, the description of what I'm doing does not necessarily imply it is correct for what you are doing, but it may provide a good reference point. The specifics which may mean that something different is required for you are that your soil conditions and climate may mean that something needs to be done differently.

As a short-term measure, when I bought this house, I had a structural engineer examine the crawlspace and create plans to be submitted for a building permit so I could do work to add beams to support the joists with 6x6 posts to support the beams with concrete footings to support the posts. The plans I got were that I would use my existing 2x6 floor joists and the existing triple 2x6 beam under the center of the house, and I would add 2 more full length triple 2x10 beams supported by posts at 7' spacing on center. The posts would be supported by 24"x24"x10" deep spread footings.

I am in Michigan so typically 42" depth would be required to get below the frost line for foundation, but my understanding is that because I have a conditioned crawlspace, frost heaving is not an issue thus the concrete footings are not required to go below the frost line.

This is also worth noting if you were to go the same route, you mentioned insulating the floor joists. To condition the crawl space you should have heated air supplied, and the insulation should not be on floor joists but it should be on the crawl space walls.

I will tell you that after moving in last November, I have 4 footings done. The plan has evolved, in all I'm going to need 22 footings for all beams.

We had also eventually planned to have a foundation wall excavated and poured. We have a contractor who does this work and will make a 12" wide by 42" deep foundation wall and install cement block crawlspace wall to the rim joist. We're investigating financing to pull that project ahead, we had originally planned to wait on that a few years. We will not be able to get mortgage financing until this is done, we are buying on land contract.

It's also worth noting that the plans we are executing are for a 1.5 story house, and based on it being a 2 story house as our eventual plans are to have the second floor torn off and rebuilt to a full second floor. Thus our load calcs from an engineer would involve higher loads than your single story cottage, but it's useful for reference.

I think your lumber sizes you're planning sound undersized, I'd expect 2x6 joists and probably triple 2x8 beams. That's without consulting any tables, it's probably overkill, but you can find joist and beam span tables if you search around - I'd recommend looking for a book on framing, that will probably have span tables too. But ultimately, what you're considering should have plans specified by an engineer and I would plan on either getting the plans yourself or working only with a contractor that includes that. The foundation wall is probably straightforward enough but you're talking about beams.

My cost for the foundation wall is $10k, and I know that it's unusually low so expect a lot more... And I don't think it's really something a lot of people do.

For reference, we did once look for quotes on doing the work of putting in the beams and footings and had a quote of $20k on that.

__________________
Please do NOT consider any "before" picture of my house as any kind of endorsement of any particular construction method. In fact, you should probably assume that if I post a "before" picture, I am posting it because I am soliciting advice on a proper replacement for one of MANY things done wrong by a previous owner.
WillK is offline   Reply With Quote
Old 07-24-2011, 02:14 AM   #3
Member
 
Join Date: May 2011
Location: Massachusetts, USA
Posts: 325
Default

Pimp my Crawlspace!


Thanks WillK. It is good to hear your story.

2" by 4" spans aren't even supplied in the MA code span tables, but they defer to the AF&PA Maximum Span Calculator for Joists & Rafters for other sizes. The spans are only 6' ft and most of the joists are 12" on center. Whether they work or not depends on the live and dead loads selected. I'm not sure how the loads are formally determined, but my estimates put the spans on the borderline. Practically the floors are nice and flat and don't bounce, but I'm not sure where it sits with the code. How do you rebuild floors from the bottom up, anyway?

I'm not sure what the proper term for them are, but there are small formed ledges on the concrete perimeter wall that are 6" deep - it looks like at one point there were 6" deep beams installed. As a matter of fact, some of the beams used to prop up the joists are old 4" by 6" beams - probably not a coincidence.

We have forced hot water (a nice new boiler system, actually), not forced hot air, so I don't know how we could condition the crawlspace without big system modifications. Though if that means we don't have to dig to 48", that might be the way to go.

Costs are a consideration, but the small size of the house changes the decision-making calculus a bit. The place is 640 sq. ft., single story. I know I could bulldoze the entire place and rebuild to the same footprint for $50k. If I had the cash on hand when I bought the place that would have been the way to go, but that wasn't the case. We like the house otherwise, and the thought was that maybe $10k or so to get the crawlspace into better shape over the next several years would be a worthwhile investment.
Thunder Chicken is offline   Reply With Quote
Old 08-08-2011, 12:38 PM   #4
I ask the impossible!
 
Join Date: Aug 2010
Location: Royal Oak, Michigan
Posts: 1,069
Blog Entries: 7
Default

Pimp my Crawlspace!


Actually, now that I look at this thread again and think back, the first house we had used a newer boiler/baseboard hot water heating system. It had an addition with a foundation and was on crawlspace, but at any rate the crawlspace was insulated on the walls and the crawlspace was heated by way of this same system. They had a baseboard heating module in the crawlspace (didn't have the covers like it did in the living space)
__________________
Please do NOT consider any "before" picture of my house as any kind of endorsement of any particular construction method. In fact, you should probably assume that if I post a "before" picture, I am posting it because I am soliciting advice on a proper replacement for one of MANY things done wrong by a previous owner.
WillK is offline   Reply With Quote
Old 08-08-2011, 01:09 PM   #5
Member
 
Join Date: May 2011
Location: Massachusetts, USA
Posts: 325
Default

Pimp my Crawlspace!


As it is my crawlspace is connected with the equipment room that contains the boiler. Without any special radiators the crawlspace never went below 45F during the coldest cold snaps we had last winter with open crawlspace vents. I stuffed some styrofoam over the vents to slow down the air flow for this coming winter. Keeping the humid summer air out of the cool crawlspace seems like a good idea and is keeping things a bit drier.

Closing the crawlspace and conditioning it would greatly simplify the pier installations (slabs vs 4' deep footers). The only concern that I have is insulating over dirt - I worry about creepy crawlies and moisture getting held against the sill and frame. The dirt in my crawlspace is very uneven and would require some grading, but it would probably need to be done either way. Grading in a 14" crawlspace, oh yeah

Why, oh why, couldn't they have done this right when the floor was being replaced ?
Thunder Chicken is offline   Reply With Quote
Old 08-27-2011, 12:26 PM   #6
JOATMON
 
ddawg16's Avatar
 
Join Date: Aug 2011
Location: S. California
Posts: 7,233
Default

Pimp my Crawlspace!


I'm a little late in the response....but I can give you some input on footings..

We are building a 2-story addition to our house....part of it required me to install 2 footings under the existing house. It was a b!itch....

Forget about trying to just pour those footings the regular way....you will need a pumper to pump it in that far...

Additionally...getting it level was not easy....nor did I really get it level....several hours with an air chissle only got me close....I ended up slaping down a layer of spec mix and calling it done. Had to shave the floor joists to make them fit. Then re-install all of the plumbing I took out just so I could access all of it.



Plumbing re-installed...



Specs on the footing....24" below ground...18" wide...wall is about 16" above dirt and 8" wide....has 4 #4 bars...2 top, 2 bottom along with anchor bolts and hold downs.

Considering that your wanting to just stiffen up the floor....I would suggest girder pads....basically, you dig a 2' deep hole about a foot square....pour it full of concrete with a piller on top and Simpson girder bracket....pour one about every 4' or so....pretty much the way you show the footings....then put girders on top. This way you can jack up the floor and adjust the height of the girders as you go along.

It might be worth getting input from an engineer on spacing and maybe more exact details of the pillers.

Here are some pics of a couple girders I had to install in addition to the footing.



__________________
"The dream is free but the hustle is sold separately."

My 2-Story Addition Build in Progress Link ... My Garage Build Link and My Jeep Build Link
ddawg16 is online now   Reply With Quote
Old 08-27-2011, 01:04 PM   #7
Member
 
Join Date: May 2011
Location: Massachusetts, USA
Posts: 325
Default

Pimp my Crawlspace!


Thanks ddawg.

If my crawlspace were conditioned I could do exactly what you suggest, but currently it is ventilated. I don't know exactly how the Mass. codes define 'conditioned'.

I am a licensed professional mechanical engineer and know how to calculate loads and such, though I will defer to a structural engineer for code compliance issues. I am not just trying to stiffen the floors - there are two bearing walls in the house that span the crawlspace that really need proper foundation support.

Part of the project would likely involve removing and replacing a section of floor at the front of the house, by the front door. With this floor out I can get anything I want into the crawlspace (concrete pump lines, forms, lumber, steel beams, etc.), anything that will fit through the front door.

There are a dozen ways to do this project, but I want whatever that goes in to be 'forever' and not cause any headaches down the road.

Last edited by Thunder Chicken; 08-27-2011 at 01:07 PM.
Thunder Chicken is offline   Reply With Quote
Old 08-27-2011, 02:18 PM   #8
JOATMON
 
ddawg16's Avatar
 
Join Date: Aug 2011
Location: S. California
Posts: 7,233
Default

Pimp my Crawlspace!


My crawl space is ventilated as well.....but then again, I live in California....biggest problem here is earthquakes, termites and demobrats....

If you are going to open it up like that.....then a poured footing would be the way to go....the girders did a good job of stiffening my floor...but that 8' footing under the bathroom wall? Wow....

In retrospect, I should have pulled off the existing floor joist (last pic, right side) but it was holding up the bathroom wall....I guess I could have shored it up on the other side as a temp measure....would have made access a lot easier...

But thinking about your situation....if you were to pour footings....you wouldn't have to be exact...you could use spacers on each floor joist. In fact, if your floor is anything like mine was...I can see you making several adjustment passes while you dial it in....and give the walls time to 'adjust' to the raising.....you should have heard the creaks from my walls as I was jacking everything up.

__________________
"The dream is free but the hustle is sold separately."

My 2-Story Addition Build in Progress Link ... My Garage Build Link and My Jeep Build Link
ddawg16 is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
getting the most out of a heated crawlspace Gerry Fossum HVAC 2 06-08-2011 07:42 PM
Crawlspace Moisture - Serious Problem PaoloM General DIY Discussions 11 12-15-2009 01:35 PM
Insulating an unheated crawlspace indignatz Building & Construction 7 10-28-2009 06:29 PM
musty crawlspace svmaine Building & Construction 2 09-03-2007 03:53 PM
crawlspace exposed to outside and damp djbauda Building & Construction 5 07-30-2007 07:49 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.