Talk to me about building a footing next to a foundation

[rothwem]

I have these sketchy steps behind my house that come down from a landing outside the back door of my house.  They're currently made of wood that is covered in algae so they're really slick, and they were never put on good footings, so they're sinking and sloped.  Yep, sketchy.  My near term plans for this house are to move out and rent it, and the only thing worse than me slipping a busting my ass is having a tenant slip, bust their ass and sue me. 

I want to tear them out and build a set of cinder block steps in their place.  The actual steps seem easy, but I'm not sure about the footing.  I was thinking I would dig down 6" or so and put some gravel in, then maybe if I'm feeling fancy, maybe a couple inches of concrete. 

Is it obvious that I'm new at this?

So here come the questions:

-Is it a big deal to dig next to the foundation of my house?  I've attached a drawing of where I want the steps to go. 
-Should I make my footing deeper?
-Should I bother with a footing?  I'm in Raleigh, and we've got red clay as our base.  Not sure if that's good or bad. 

Anything else I'm missing?

[Spork]

Warning: I'm not a structural engineer or a building contractor.  Take my advice at your own peril.

I suspect 6 inches or so is fine for Raleigh.  You want to be below the frost line.  If you're worried, 12 inches is not that much more difficult. 

Frost line map:  http://www.decks.com/how-to/264/deck-footing-frost-depth-map

I wouldn't want to build on clay without some sort of firm footing.  Clay can be expansive.  It expands and contracts with wet/dry seasons.  This is likely to be just as big a problem as heaving due to frost.  (I've paid dearly for foundation repair in clay soil.  Trust me.)

I'd also try to tie it to your existing foundation if you can.  By that I mean anchor your rebar into it by drilling into it a bit and somehow mechanically fastening the rebar and the existing foundation.

[trollwithamustache]

If you do use gravel, in general you want to send water away from your house and its foundation. So, if you end up doing a big sub base of some kind of aggregate, you'd want the hole to slope away form your house and you'd fill it level with the rock.  Don't slope it accidentally towards your house.

All cinderblock will be heavy, so a footing may be nice to prevent settlement over time.  Whats wrong with putting in some decent footings, building new wood steps and putting some kind of grippey surface on the steps?  Is there something other than rain that's putting lots of water on the steps?

[rothwem]

I'd also try to tie it to your existing foundation if you can.  By that I mean anchor your rebar into it by drilling into it a bit and somehow mechanically fastening the rebar and the existing foundation.

Hmm.  I was actually going to try to not do that, thinking that since my foundation is pretty deep, and my footing wouldn't be that deep, wouldn't they want to move different amounts and then want to seperate themselves?

If you do use gravel, in general you want to send water away from your house and its foundation. So, if you end up doing a big sub base of some kind of aggregate, you'd want the hole to slope away form your house and you'd fill it level with the rock.  Don't slope it accidentally towards your house.

All cinderblock will be heavy, so a footing may be nice to prevent settlement over time.  Whats wrong with putting in some decent footings, building new wood steps and putting some kind of grippey surface on the steps?  Is there something other than rain that's putting lots of water on the steps?

Thanks for the pointer on the footing. 

As for replacing with wood steps, I've thought about it, but the backyard is nearly 100% shaded, and in the summer, the wooden steps never seem to dry off, why is why I suspect they're covered in algae. 

[Metric Mouse]

http://forum.mrmoneymustache.com/do-it-yourself-forum!/i've-built-a-set-of-cinderblock-stairs!/msg1062192/#msg1062192

Seek, and ye shall find.

[rothwem]

http://forum.mrmoneymustache.com/do-it-yourself-forum!/i've-built-a-set-of-cinderblock-stairs!/msg1062192/#msg1062192

Seek, and ye shall find.

Ha, I actually did look at that before I made this thread.  No offense to the original poster of that thread, but those steps are not exactly the look I was going for.  I was thinking something like this:

 

[paddedhat]

I'd also try to tie it to your existing foundation if you can.  By that I mean anchor your rebar into it by drilling into it a bit and somehow mechanically fastening the rebar and the existing foundation.

Hmm.  I was actually going to try to not do that, thinking that since my foundation is pretty deep, and my footing wouldn't be that deep, wouldn't they want to move different amounts and then want to seperate themselves?

A block or concrete "addition" to a masonry foundation, no matter how small, should be attached to the original foundation. In the case of an existing formed concrete wall, standard practice is to drill the wall and insert rebar "pins" to tie the footer to the wall. If the existing structure is a block wall, the face of the block is removed, where the footer meets the wall. This allows for a shelf on the existing wall, to support the end of the new footer. If this step is ignored, you can anticipate settling, sometimes drastic, often slight, but continuing for years. Remember, you are not in undisturbed "virgin" ground, you are adding hundreds, most likely thousands, of pounds of weight on fill that was dumped there after the existing foundation was completed. The other option would be a precast set of steps and small porch. They are delivered and installed by the manufacturer and are significantly more durable that building out of block. The mold issue may very well reappear on anything you build, and you may be pretty disappointed at how poorly a block stair surface performs with continual pressure washing to clean off organic growth on the surface.

[Fishindude]

The other option would be a precast set of steps and small porch. They are delivered and installed by the manufacturer and are significantly more durable that building out of block.

I've done a bunch of these and will assure you that these will be much higher quality and better looking than anything somebody not experienced in the building trades will put together.
They have all different shapes and sizes, with or without landings, with or without railings, etc.  I would set these on a concrete slab "pinned" to the existing foundation so they don't move around and caulk the joint between precast stairs and home foundation with a good urethane caulk.

[paddedhat]

Rothwem, regarding the pic. you posted. If this was done in a code enforced area, it would only last until the code officer red flagged it, as it's a dangerous setup for many reasons. The riser height is at about the max. at 8". The treads are seriously undersized at 8" deep. The closed risers create a need for a bullnose on the treads. Finally, there are no rails. Pretty much the whole thing is an accident waiting to happen. For any user who is accustomed to properly built stairs, tripping up, and falling down a mess like that, is not only possible, but likely.

[Spork]

Rothwem, regarding the pic. you posted. If this was done in a code enforced area, it would only last until the code officer red flagged it, as it's a dangerous setup for many reasons. The riser height is at about the max. at 8". The treads are seriously undersized at 8" deep. The closed risers create a need for a bullnose on the treads. Finally, there are no rails. Pretty much the whole thing is an accident waiting to happen. For any user who is accustomed to properly built stairs, tripping up, and falling down a mess like that, is not only possible, but likely.

The stairs in my house (which I built and am 100% to blame for) have a bull nose... but it isn't big enough.  About once a day I accidentally scrape my heel on one step somewhere along the way.  It's wood, so ... it doesn't catch or hurt much.  If it were concrete, it would peel the skin off my foot/ankle.  Yeah, the bull nose is there for a reason.

The pic looks like it might be a trailer house.  If not, it's probably a pier and beam with a brick skirting around it.  (I also like the brown metal flashing -- or whatever it is.  I bet it's covering areas where the dog chewed off the trim.)

[rothwem]

The other option would be a precast set of steps and small porch. They are delivered and installed by the manufacturer and are significantly more durable that building out of block.

I've done a bunch of these and will assure you that these will be much higher quality and better looking than anything somebody not experienced in the building trades will put together.
They have all different shapes and sizes, with or without landings, with or without railings, etc.  I would set these on a concrete slab "pinned" to the existing foundation so they don't move around and caulk the joint between precast stairs and home foundation with a good urethane caulk.

Yea, I looked at those first, but they're $$, and a poured footing is also $$.  I was hoping to keep this project <$1000.  If I can't do block for under that, I'll just re-build the wooden steps and consider them a 5 or 10 year "wear item".

[rothwem]

Rothwem, regarding the pic. you posted. If this was done in a code enforced area, it would only last until the code officer red flagged it, as it's a dangerous setup for many reasons. The riser height is at about the max. at 8". The treads are seriously undersized at 8" deep. The closed risers create a need for a bullnose on the treads. Finally, there are no rails. Pretty much the whole thing is an accident waiting to happen. For any user who is accustomed to properly built stairs, tripping up, and falling down a mess like that, is not only possible, but likely.

Ha, yea, the pic is literally the first semi-attractive looking concrete block staircase I found a picture of when I googled.  I have no idea who's house that is. 

[Le Poisson]

I suggest interlock rather than what you are thinking.

For interlock you don't need as robust of a footing, and if things move you can reset it.

I built a 100' (linear) interlock retaining wall/garden system in our backyard (Toronto area) about 4 years ago with shallow footing (1 row of blocks set below grade, on top of tamped A Gravel base with screenings as a setting layer) and it hasn't moved at all. As long as teh spot is well drained (you may need to trench a section of O-pipe to a ditch or swale) and the base is well compacted, you'll be fine.

As a bonus, interlock comes in a myriad of shapes and colours and can be more visually attractive than some of the cinderblock stoops I've seen, with far less work than some of the nicer cinderblock stoops I've seen.

You can link to our project in our family blog here - It is not particularly well written or documented, but its all there.

[rothwem]

I suggest interlock rather than what you are thinking.

For interlock you don't need as robust of a footing, and if things move you can reset it.

I built a 100' (linear) interlock retaining wall/garden system in our backyard (Toronto area) about 4 years ago with shallow footing (1 row of blocks set below grade, on top of tamped A Gravel base with screenings as a setting layer) and it hasn't moved at all. As long as teh spot is well drained (you may need to trench a section of O-pipe to a ditch or swale) and the base is well compacted, you'll be fine.

As a bonus, interlock comes in a myriad of shapes and colours and can be more visually attractive than some of the cinderblock stoops I've seen, with far less work than some of the nicer cinderblock stoops I've seen.

You can link to our project in our family blog here - It is not particularly well written or documented, but its all there.

Do you have a link to the interlock stuff?  Google images just shows something that looks suspiciously like fancy cinder blocks. 

[Le Poisson]

I suggest interlock rather than what you are thinking.

For interlock you don't need as robust of a footing, and if things move you can reset it.

I built a 100' (linear) interlock retaining wall/garden system in our backyard (Toronto area) about 4 years ago with shallow footing (1 row of blocks set below grade, on top of tamped A Gravel base with screenings as a setting layer) and it hasn't moved at all. As long as teh spot is well drained (you may need to trench a section of O-pipe to a ditch or swale) and the base is well compacted, you'll be fine.

As a bonus, interlock comes in a myriad of shapes and colours and can be more visually attractive than some of the cinderblock stoops I've seen, with far less work than some of the nicer cinderblock stoops I've seen.

You can link to our project in our family blog here - It is not particularly well written or documented, but its all there.

Do you have a link to the interlock stuff?  Google images just shows something that looks suspiciously like fancy cinder blocks.

That's what they are. But they take no mortar, and by design each row locks into the next. If you ever need to reset them, you can just lift them apart. On ours we used masonry caulk to glue caps onto teh top of teh wall. Where we needed steps we filled the space with rubble and sand, vibrated it in place, then laid caps over teh sand to create teh flat - continuing with more blocks to form the step.

Being in Toronto, my sources may not be worth much to you, but all of our stone came from the reject pile in the back of Armetecs' yard for 50% off. (I'm cheap like that, I don't mind a bad dye lot) Here are their pre-made steps: https://www.armtec.com/product/prostack-concrete-steps/

Play with their website to different products and applications.

[Cadman]

If I were in your shoes, I would go with a precast unit (few hundred $$) and forget the blocks, not only for safety reasons (riser height, lack of cast-in tread) but for longetivity reasons as well. Every joint in an assembled unit is one more point of failure and you better be spot on with mortar consistency and be able to work quickly for something that stands half a chance.

I also don't think I would put in a footing nor pin the unit to the structure. I would go down a couple inches, use paver-locking sand and tamp the hell out of it, then place the steps. If it lifts or falls, it will do so consistently. In our area with a 42" frost line, I see a 1/2" change between floating slab and 48" deep walls. I'd imagine it'd be even less in your area. YMMV.

[Le Poisson]

If I were in your shoes, I would go with a precast unit (few hundred $$) and forget the blocks, not only for safety reasons (riser height, lack of cast-in tread) but for longetivity reasons as well. Every joint in an assembled unit is one more point of failure and you better be spot on with mortar consistency and be able to work quickly for something that stands half a chance.

I also don't think I would put in a footing nor pin the unit to the structure. I would go down a couple inches, use paver-locking sand and tamp the hell out of it, then place the steps. If it lifts or falls, it will do so consistently. In our area with a 42" frost line, I see a 1/2" change between floating slab and 48" deep walls. I'd imagine it'd be even less in your area. YMMV.

For a precast unit, the job becomes very DIY friendly with a 4 hour rental of a forklift or bobcat. Also, most precast places offer delivery, and if you have the Gravel bed prepped they can drop in place. Or you can do what we did and have everything delivered to your driveway and spend the next 2 months building something magnificent.