Redoing a deck and thinking about stair details...

[Innovate1]

Have an existing deck and looking at replacing it. It's about 20 years old. All the treads are 42" wide but the way the railings are done the upper width, railing to railing is about 36 and the lower section is about 30. The reason is the railing for the top section on one side is not on the stair but beside it. I suppose it's not that big of deal but it always has bugged me the lower section is obviously tighter than the upper section.

One corner of the landing is suspended from the framing above. Seems like aluminum railings are more popular these days and was told there isn't a way to mount it the way the current one is done. One company said they needed to add a post there - core drill the patio and pour a belled pier - but don't really want to do that. They said they couldn't wrap the hanging post the way it is now with composite (but they use composite to cover support posts so that seemed like a weak excuse). Real issue is the aluminum railings fasten to matching posts and those can't go there or hold up the landing like that. They want to put railing posts on both sides of the stairs making the upper section narrower which would match the lower.

I could make the lower section wider by moving the upper section back about 6 inches. I suppose the width difference is not that big of deal but it always has bugged me a little that the lower section is obviously tighter than the upper section.

I ran the numbers for loading for the hanging support and it's well below any stress limits. It only has one bolt top and bottom and I think 2 each place would be better.

Figured I might get some ideas posting here...

 

[Fav Onefour]

Tough setup. It does not look like there is even a ledger board where the landing is against the wall. What is supporting that side?
Are they talking about just replacing the decking and not the frame for your replacement?
The idea of moving the upper stair back makes sense, If you are replacing all the framing, look at orienting the stairs with a different configuration.

 

[jar944]

That is very non conventionally framed..

 

[larry4406]

Wow!

Is the landing "hung" from the upper deck thru the circled post?

At the day job, we have/had a house type where the main stair landing is hung from above.

 

[PCustoms]

Oh no, not deck stairs again...

 

[tarmy]

Oh no, not deck stairs again...

Should be along in 3….2…1….

 

[Innovate1]

Wow!

Is the landing "hung" from the upper deck thru the circled post?

At the day job, we have/had a house type where the main stair landing is hung from above.

Yes. One corner of the landing is supported by this post from above. Double 2 x 10 above and that ends in a double 2 x 10 joist at the top of the upper stairs. I ran the numbers and it's well within allowable loads for 10 psf dead load and 60 psf live load. Deterioration over time might be a concern but it's been there 20 years and is still very solid. One of the possible contractors pushed and tugged on it - apparently he thought it might move. Then threw out two names that he thought wouldn't approve it (pretty sure those aren't inspectors for my area) and how code had changed. Also said notched posts for support are no longer allowed although that would be easy to avoid. Would like to avoid another post if possible - it really blocks the area.

There is a ledger for the landing.

Totally different issue - they recommended "Composite ledger board". Had to look that one up - fiberglass reinforced structural material.
Expensive and treated wood is going to last longer than I will likely be around so no to that.

Had thought about some sort of way to keep the under deck area dry not sure it's worth the cost/trouble. The underdeck panels reduce the ventilation of the underside which would age it faster. Could probably come up with a cover for the wood rack that's a bit more attractive than a tarp and call it good.

 

[strutaeng]

Ok, so if the "hanger" works on the numbers, then that issue goes away.

I'm a bit out tune with the IRC in the latest editions with any prescriptive portions, but the code is mostly concerned with height of guardrails/handrails and clearances, and I'm pretty sure everything still needs to meet the 200 lb horizontal point load or 50 lb/ft like the IBC. (Edit: 50 lb/ft is only a IBC requirement, not in the IRC according to Google.)

Why can't they built it with wood materials as it's built now? I don't really see anything glaringly wrong or unusual with how they built those TBH, aside from the hanger.

Maybe some hand sketches on the handrail balustrade option you are thinking may helps folks see what you you have in mind?

If they made the lower section narrower, then the only option there is the tear it down rebuild it to match the rest.

 

[Innovate1]

Ok, so if the "hanger" works on the numbers, then that issue goes away.

I'm a bit out tune with the IRC in the latest editions with any prescriptive portions, but the code is mostly concerned with height of guardrails/handrails and clearances, and I'm pretty sure everything still needs to meet the 200 lb horizontal point load or 50 lb/ft like the IBC. (Edit: 50 lb/ft is only a IBC requirement, not in the IRC according to Google.)

Why can't they built it with wood materials as it's built now? I don't really see anything glaringly wrong or unusual with how they built those TBH, aside from the hanger.

Maybe some hand sketches on the handrail balustrade option you are thinking may helps folks see what you you have in mind?

If they made the lower section narrower, then the only option there is the tear it down rebuild it to match the rest.

The local, small city within the metro area, is still on the 2012 building code. But I suspect the surrounding ones are more current, at least some of them. I knew we lagged some but saw surprised to see it that old. I also see on the cities web site that they now have some online permit system that looks like it is a contracted thing not done by the city. Lots of missing information and broken links so apparently in transition. And am told they have a new younger guy for inspections. When I did my detached garage about 5 years ago the system was really easy.

They could rebuild with the materials as it was done. But it seems some of the industry moves cause complications. Most are pushing aluminum railings that have bottom flanges that are screwed down through the deck. That and running a strip of decking around the outside means they need more blocking underneath. One company said they figured $500/step with all the blocking and 45 degree cuts of decking needed. Some suggested "picture frame" around the whole deck although it seems it's really most obvious on the outside edge. One place said they ran a 4 x 4 horizontally at the top between two joists around the outside to give solid area to run railing screws into. They use joist tape but that leaves a joint space between boards over the wide framing with no drainage. Seemed like they didn't worry about that but said they could cut some grooves in the underside of the decking. I need to look at their on line pics to see if they run the 4 x 4 the full length. I got the impression they did so they didn't have to worry about where the posts end up but if they don't that would allow drainage where the 4 x 4 isn't.

The stair treads are all the same width - 42". The difference in space between railings is because there are railings on both sides of the lower section and come in about 6" on each side. The upper section has the inboard railing outside the treads so is about 6" wider. With the flange mounted railings they would need to put both on both sections which would make them equal but 30" seems a little narrow to me. People could pass one another but not really easily.

 

[jar944]

For the railing posts, you should be able to bolt a 6x6 between the joists as blocking. If you can bolt to 2 joists and a band even better. no need to picture frame the treads.

They can wrap the hanging post, they just can't use a cheap pvc sleeve.

 

[Innovate1]

I'm coming around to the idea of an extra post to the patio. It isn't really needed but easier to go with that.

The contractors said they would core drill the slab and then flair the hole for a bigger base. But they said it wouldn't be completely covered by the 6 x 6 post. A 6" hole does seem a little tight but doable and would be covered (if located exactly right). I will try to find pictures of the slab install - I may have pics showing existing footings but not sure I will have them and not sure there is one in that location. But since it is only supporting one corner of the landing it's tempting to say there is a footing. Seems with that little load the slab should be fine. And it hasn't cracked anywhere.

 

[mm08822]

Oh no, not deck stairs again...

Let me guess, you're afraid of the bad stares he's gonna get

 

[larry4406]

I'm coming around to the idea of an extra post to the patio. It isn't really needed but easier to go with that.

The contractors said they would core drill the slab and then flair the hole for a bigger base. But they said it wouldn't be completely covered by the 6 x 6 post. A 6" hole does seem a little tight but doable and would be covered (if located exactly right). I will try to find pictures of the slab install - I may have pics showing existing footings but not sure I will have them and not sure there is one in that location. But since it is only supporting one corner of the landing it's tempting to say there is a footing. Seems with that little load the slab should be fine. And it hasn't cracked anywhere.

What is the current "hanging member"? A 4x4 post?

Perhaps get a piece of 1/4" steel plate to hang it if the current hanger is only a wood post. Sister the presumed wood post with the steel plate and bolt all solid.

If you are gonna have inspections, it will fail the sanity check and they will want a red stamp drawing.

 

[Innovate1]

What is the current "hanging member"? A 4x4 post?

Perhaps get a piece of 1/4" steel plate to hang it if the current hanger is only a wood post. Sister the presumed wood post with the steel plate and bolt all solid.

If you are gonna have inspections, it will fail the sanity check and they will want a red stamp drawing.

The current arrangement has a 4 x 4 post. Fastened to double 2 x 10 above. I haven't had any crazy parties with packed deck but it has been fine for 20 years and is still solid. It supports one corner of a 42" x 42" landing and one corner of a similar size upper stair - 1/4 of the total load of both which is tension at 70 psf loading is 430 lbs. I had considered using hold down brackets and galvanized threaded rod, possibly inside some sort of sleeve. As far as inspections and stamped drawings the rules here were that engineer stamps weren't needed for owner occupied residential plans. But things are changing on the city web site and I heard they hired a new guy so not sure what is now needed. It was all inspected when built 20 years ago and was no issue - maybe they missed it. I don't recall if the inspector made any comments about it or not.

As for the allowable tension on the 4 x 4 google says (search term "allowed tension is 4 x 4 #2 post) for #2 4 x4 it is between 850 and 2000 lbs and references a Simpson page that shows values around 10,000 lbs so they don't agree at all that I can see. https://www.strongtie.com/products/...on-connectors/technical-notes/post-capacities
In any case the stress is low. If I need to put a post to below it hardly seems it needs a footing for loading of 430 lbs on the slab.

 

[jar944]

. If I need to put a post to below it hardly seems it needs a footing for loading of 430 lbs on the slab.

At least around here a landing is considered a deck in and of itself and minimum footing for a deck support post is 12x12" or 14" round.

So.. I have 14" diameter footings for a 4'x4' landing.