Creating Walkout Basement - Need Advice

[kwolfe]

I have been considering creating a walkout basement for some time now. My basement is 30' by 37'. I would like to put in two windows and a door in order to provide easy access and additional sunlight. I will try and take some pictures this afternoon, however I attached two drawings that give you an idea of the house layout. The door and windows will be on the side of the house which does not bear the load of the floor joists. The openings would also not be directly underneath the support beam that runs the width of the house. The grade of the house on that side should allow me to have a true walkout (no steps, or bilco needed). Oh yeah, the foundation is poured 10" thick walls, 9' high. The blue marking in the first picture are my proposed door and window sites. The second picture gives you a rough idea of what I will be excavating.

My questions (that I can think of) are the following:
1) Since I am located in PA (where it does freeze), do I need to worry about exposing the side of the foundation to frost?
2) Are there any tricks to cutting ou the openings?
3) What sort of additional support do I need once the openings are cut (headers, side support)?
4) What else am I not thinking of (probably plenty )?

 

[MarkV]

Well I don’t think you need to worry about the frost problem. For a 10” thick wall with rebar you are going to have to have a concrete cutting company come and make the cuts. The cuts will require some specialized equipment that you don’t get at the rental store. There are enough variables that I would not consider doing it with out an engineer involved and if your area requires permits they will require it engineered.

It does look do able and you are lucky to have the 9’ ceiling to make it practical.

MarkV

 

[RobS]

Kevin, I got your PM. You saw my thread on cutting windows in my buddy's basement. His was only 8" thick but that saw should work on 10" as well. Not sure about renting but you could buy the saw and resell when finished. You'll probably eat up the diamond chain completely with all your cutting. He was told he could get about four windows out of one chain.

Frost will be more of a concern for the footer, you might check your codes and measure your depth. Stud and insulate the inside of the walls and you should be good.

Sounds like a fun project, keep us posted.

 

[tlbuser]

I
My questions (that I can think of) are the following:
1) Since I am located in PA (where it does freeze), do I need to worry about exposing the side of the foundation to frost?
2) Are there any tricks to cutting ou the openings?
3) What sort of additional support do I need once the openings are cut (headers, side support)?
4) What else am I not thinking of (probably plenty )?

1) Frost/freezing won't be an issue on the outside. You will want to add paint, siding, brick or stone though ($ -$$$)

2) Yes, you should get a structural engineer to approve it. A concrete chainsaw will do the job. Not sure if you could rent one in your area, if not ($$$)
http://www.icsbestway.com/en/images/ICS_GC_ProductGuide.pdf

3) Again, the structural guy will be the best source for that info.

4) Consider two 5-6 foot french /patio doors instead of the door and window idea. More light and if you ever "split" the area, you'll still have an ingress/egress point with little added expense for the cutting. Add a drain grate between the doors and new patio area, a reasonable source for these is a good pool builder in the area.

 

[LK3054KIOTI]

Kwolf I have a house with a walk out and when they where putting in the footings on the walk out side the had to dig down below the frost line to keep the footing from heaving, if you don't already have this I would check on it. or am I misreading your post, is your basement wall already exposed? and you are just wanting to cut the holes if so have at it as long as the support beam has plenty of support under it not above a window or door

 

[woodlot]

Two people have said that freezing will not be a problem, I don't undersstand that. If you excavate one side of your home to create the walkout, I'd think you'd end up with a footing on grade. I'm no engineer, but I'd think that'd be a less than ideal situation.

 

[tlbuser]

Two people have said that freezing will not be a problem, I don't undersstand that. If you excavate one side of your home to create the walkout, I'd think you'd end up with a footing on grade. I'm no engineer, but I'd think that'd be a less than ideal situation.

I based my answer on the assumption that the walls are poured on top of the footers, assumption being that the poured walls were for the basement and that any excavation won't affect the footers and assumption was made that footers are 24 - 36" (or area code) below the lowest point of the wall. Another reason to consult a SE/PE. And no, there should not be any problems on the exterior except for appearances sake. BUT, this exposes another portion of the whole house to the elements and will probably have a negative effect (albeit small, dependent upon direction of exposure to the sun) on the total heating/cooling load for the house.

 

[dtd24]

You will definitely have to worry about frost. If you dig that out you will expose your footing. If I were you, I would pour a 4' wall under whatever I took out. We usually use a 2x8 wall in our walkouts with double 2x10 headers over each window or door opening. Rent a cut off saw to do the cutouts. on the exterior you can pin furring strips to the foundation and side with whatever your building is currently.

Permit = raise in taxes

 

[kwolfe]

You will definitely have to worry about frost. If you dig that out you will expose your footing. If I were you, I would pour a 4' wall under whatever I took out. We usually use a 2x8 wall in our walkouts with double 2x10 headers over each window or door opening. Rent a cut off saw to do the cutouts.

I would be exposing the side of the foundation to just above the level of the basement floor. The basement walls are poured on top of footings correct? Also, are you saying to extend the footer by 4' under any opening I cut?

I plan on over framing whatever opening I make. I figure with 10" thick walls, I would make the header and vertical supports the same thickness. Probably overengineering it, but that cannot be a bad thing.

 

[Builder]

If I understand you correctly and you fully expose your basement walls outside by digging out all the soil to the same level as the inside floor, then yes, you will then have a frost issue.

What you need to know is what the code minimum is for footing depth in your area, then you can underpin your wall to the correct depth. I'm underpinning a garage as we speak in this thread:

http://www.tractorbynet.com/forums/projects/103038-old-world-craftsmanship-how-not.html

If your joist tips are over the doorway you want to cut, one way you can support the opening is by installing a header just inside the doorway. You can saw cut 2 holes in the floor where your lally column poles that support the header will go on each side of your opening. You make the holes 2' x 2' x 3' deep and fill them with concrete. Once the concrete dries, the lally column poles can sit on their new footings. Then you can get a piece a C channel (rated for the load over the opening) and bolt it to the lally column poles (just like the lally column poles you see in the middle of a basement to support your joists. Then, if there's a piece of concrete header from the outside wall still remaining, you weld a 4" angle iron to the back side of the C-channel. This will sit under the remaining concrete up above and hold it from cracking & falling down.

You'll ned to get a sketch & small set of plans together. Call a local PE and ask him for assistance. Or I can give you a name you can call. He'll do some plans for you for pretty cheap.

 

[jwm561]

Hey wolfe, as handy as you have become since college, this one is above your skill level. First, give me a call, I'll give the name of a very reasonable structural engineer who will let you know what size lentels you'll need above windows and doors. Second, definitely hire a concrete cutting company for the penetrations, worth the money in the long run. Chesco Core Cutting is near here, but they travel all over the place. Lastly, this would be a great trial run for my new 110TLB depending on how much dirt you need to move. Let me know, looking forward to the 14th.

 

[Egon]

Definitely a good idea. Involve the suitable signers of plans and use a contractor for the concrete work.

Turns a hole in the ground into usable floor space.

 

[kwolfe]

OK, here are some pictures of the side of the house. From others input, it sounds like I am going to need to extend the footers due to frost...#$%@!*&^% . That is a pain in the neck.

The pictures show the slope away from the house as well as the interior basement wall. After eyeballing it this afternoon, it looks like the top of the proposed door would be where the top of the existing window is (right below the band board). This would mean putting one or two steps down once in the basement. Don't know how much of a difference that makes for the footings issue. I put a snow shovel for height reference in the one pic.

 

[Egon]

Before the hair tearing begins enlist the aid of someone competent with the building codes of your area.

 

[tbalz]

I just built a house in Upstate NY. I have a full walkout one the front of my house. My footings on that side are 12" thick and go down 48". They also wrap around 8' on either side to account for the slope of the land. That is a lot of concrete. My father in-law is a Structural Engineer and State certiefied Professional Engineer...This is a code requirement. You need to have footings down to the frost line. So any walk out area whether you have just a man door, half walk out, or full walk out has to have footings under the opening/wall down to the frost line.

 

[rico304]

Kwolf, did you decide to go forward with this project? Why or why not?

Just wondering

 

[kmdigital]

Based on your pictures, you don't have enough fall, at least in what is shown, to get a walkout basement. I would say that from what I can see, you have 5' at best, which puts you ~2-3 ' shy of getting down level to your basement floor. Maybe you can go out further than what is shown to get lower, but then you are talking very long retaining walls.

In addition, I think your walls are standard 8" walls, at least that is what they appear to be based on what I can see at the edges of the window.

Unless money isn't an issue, I would suggest putting in about 2 or 3 egress windows with long window wells. This will let in a lot of light as well as potential ventilation and possible future bedrooms. Plus it will be a TON cheaper than building long retaining walls and you won't have to worry about footers because they will still be covered with ~2-3 feet of dirt.

Also, you don't need to worry about lintels,etc, unless you were planning to remove the entire wall. The only support on this wall is at the center where the steel I-beam rests. The rest of the wall is primarily to hold back the dirt.

The main thing with egress windows is to make sure you have drainage so that they don't fill up and flood water into the basement. But that is easily taken care of with stone and drain tiles at the bottom to either the footer drain or a drain down over the hill to a point that is lower.

IMO, building a walkout here is not a DIY job, unless you are very, very accomplished and have a LOT of time. Adding egress windows, on the other hand, is relatively simple with the hardest part being to cut the wall. The best way to do this remove the dirt first, then cut the wall and drop it outwards so that you can drag the big piece away. Or maybe leave it at the bottom of your window well as a floor. It's a thought, though I've never seen anyone do that.

You can hire someone to cut this, or with an 8" wall, rent a rotary diamand saw and cut through from both directions. Just measure well, and it will work out if you can cut straight. I even have a 14" Partner wet/dry diamond saw I will sell you! Definitely use wet cut inside, otherwise you will get concrete dust everywhere in the basement!

 

[RPK]

As mentioned previously frost protection will be a big considerstion. In CT the bottom of a footing in a foundation must be 42 inches below the final grade. PA should be similar. This would be an almost impossible project to do, not to mention big $$$$. You may want to consider adding a small single story addittion on that end of the house. Maybe extend out 4,5, or 8 feet. This would enable you to add a new frost protected foundation and footing. Then you could build a wood framed wall with windows and doors. You may want to consider a small shed roof to extend back to the main house.

As far as lintels (headers) are concerned, their size is based on the load they need to support. The wider the opening the more weight they need to support. If you remove the entire existing concrete wall you could probably use a LVL beam and maybe three lally columns to support the load from above.
RPK