16 x18 Firepit /bbq deck - Design review - pick holes - feel free !

[UK4X4]

So I've been busy posting Questions

and busy dwg too

This is basicly a post and beam deck with a roof- multiple doors to close it up in the winter

Barn doors will be 4" thick insulated-

the french doors - not sure yet what type

Here's some of the parts if too small to read on the dwgs !

The center beam is not actually required - but added in case of heavy fireplace- and spreads some more load.



Roofed deck design

Snow load
90# per sq ft according to permit office
Cold roof -slippery steel
PS=CsPF
PF =90
CS=0.66 based on 8/12 roof
= 59.4# snow load plus 15 DL = 75#








Footings

Concrete posts  10"sonotubes with Bigfoot BF24 or Square foot22's
Roof load 20ft x 22ft wide @ 75# snow LL&DL= 33,000#
33,000#/ 10 posts = 3,300per post
Deck load
16ft X 18ft @ 50#LL and DL=14400
14400lbs /11 posts=1310 # per post
3,300# + 1310# = 4610# per post
Ground support is 2000# from soil report

Bigfoot footings as per below spec BF-24 gives 6283# per post
Total load is 33000+14400 =47400#
Bigfoot support =10X 6283# =62,830#
Giving a 32% over support
                                    Frost depth is 48"  
Ridge beam
16 ft wide 9 ft tributary load
144 sq ft
144X 75# =10,800
Moment 10,800X 16/8= 21,600#
3 off  1.75 X 11 7/8" LVL 1.5E @ 7243/LVL=   23,172

Check on Ridge beam support post footings
20 ft wide to include eaves X 9ft tributary = 180sqft
180 X 75# = 13500
4 posts = 3375 +1310 deckload =4685# per post OK


Eave beams

8ft span

8X7 = 56 sqf
75# x 56 ft = 4200

Moment 4200x8/8= 4200

3(2x10)

Footing to post brackets
Simpson ABU66 adjustable post base with a 5/8" J bolt in the cement




Posts to deck beam
Simpson HUCQ210-2-SDS

Posts to front and rear upper beams dropped below the post beam bracket
Simpson HUCQ210-2-SDS



Deck support Beams
2 (2x10) Hem fir treated

Posts
6x6 treated

Upper beams
3(2X10) Hem fir no 2

Rim boards
2x10 hemfir no2 treated

Joists
2X10 Hem fir no 2 un treated on 16OC

Decking
¾' treated plywood

6" Post to 4" beam
Simpson strong tie PC-46



Rafter ties
Simpson H1 rafter tie---  

Footings cement

   Cubic Feet Required:   57.5     

Cubic Yards Required:   2.13      
Number 60 lb Bags:   115      

[duncanshannon]

cant read all that tech. spec for the life of me but the drawings seem pretty cool!   

I really like the building with the doors that open all around it.  How are you going to be using this building??

[UK4X4]

The tech is - due to being in a code area

and seemingly the major hurdle in a self build in CO

- Don and others have been extremely helpfull in understanding building loadings.- it still may be completely wrong ! hence poke holes !

Use - due to my hired engineer not comming up with the goods

I'll be too late to build the planned house this season

So this is a BBQ-fire-pit / summer winter covered deck

being that its behind the 'house"it will have to be built first.....

elavation is 8500ft with  90# ground snow load

So summer all open

and winter shut in as required- the fire place / pit BBQ design is still up in the air

To the LHS I'll be adding a cover for the trailer I bought too, just not drawn yet

Ie the trailer will have the bedroom , kitchen , bathroom - and the scovered deck  will provide a larger living area
winter or summer - till the house is built

[Pine Cone]

We built something similar, but with our mild winters there was no need to enclose it.  16'x16' and we use it all of the time.  Great to have a place that is out of the rain and we ended up using the space to help build various projects since it was a dry, clean, flat place.



We really like the built in benches which also act as railings.  The benches add to the usable space since we don't need to have as many chairs on the deck. Still need to put some sort of railing on the western end.

Is the deck high enough off the ground to require railings in most of your door openings?  Seems like that could be a problem. 

Have you considered doors which could be removed and stored under the deck during the summer?  Seems like you might have problems with the doors blowing around in the wind when they are open, but they could be tied/latched together in pairs.

My bet is that you will really enjoy yours when you get it finished. 

[muldoon]

That thing looks as fancy as a french poodle.

Where does the bbq go? 

[Don_P]

I haven't taken the time to more than glance but the doors popped out also. I did this on the side of a barn and regretted it, the wind plays havok with the doors. There needs to be enough wall to slide them against or similar. Those wall/door panels might be removeable as Pinecone mentioned.

[UK4X4]

Yes the doors are a concern for me too

I have another design with sliding barn doors, which on the ends simply open half the wall

The only issue I found was sealing them.

Google searchs came up pretty slim with how to get a well sealed sliding door for the winter

The only option that sounded like it might work was using a length of chain between the rollers and the door its self

Which when the door was slid in place you could use over center clamps to pull the door in against seals

ie the door could be made 6" larger all the way arround, with a dual layer of seals outer edge and inner edge, the door gets slid into place - then from the inside the door is hooked up and pulled back against the seals



The person who did it wants to change the chain to some strap steel and add two hinges to make it still when pushed but still allow the backwards movements

Height off the ground is 20inchs unless I run with joist hangers and then it would be 12-14"- do i need a railing for 2 ft ?

French poodle - dam cheeky !

BBQ-fireplace inside - still not found something I like or suits what I want yet

Imagine a OLD UK pub with an open fireplace - with a deep hood which would allow you to bring coals forward out of the fire to cook over, with fumes etc still entering the wide hood- then put it a waist height ....

[JRR]

I agree with concerns of fall hazard thru open doors.  You might change to windows that swing upward and can act sun screens.  I would prefer regular decking boards to plywood ... just my choice for such a casual place.

[UK4X4]

Ply is because I'll be insulating underneath for the winter usage, maybe I'll do T&G over the top or similar.

another vote for a lower floor ----

oh well lots of hamering in little joist hangers- and change to treated as will be close to the ground

[Don_P]

On railing height req'd; from memory, 30" above grade, grade is measured as any area within 3' of of the edge of the deck...for instance my SIL's deck is less than 30" above grade immediately below the edge of the deck but within 3' of that edge it drops 27' over a cliff, railing definitely required! Extreme example but hopefully explains the intent.

Sliding glass doors? Some modification of shoji?

[UK4X4]

"Sliding glass doors" no

On the sides where the double hinged barn doors are, I concidered and drew up
just having 1 fixed bay and one sliding

On each side- just the sealing put me off

With input from you chaps - I searched further and found some adjustable trollies
which means if i plan right I can run loose doors in summer , then in winter adjust inward and lock in place
If I have 6" of overlap I can have 3 seal faces for example.

Ok so my original was 3" clearance + 10 + 10 so within code but with ground slope I might have issues on the low side of the lot

so I'll re-draw with hangers

Then that brings in if I lower the floor and lower the front & rear beams a loft becomes possible- not great headroom but as a sleeping bay it would be perfect- something to calculate the loads for now and add in after the inspector !

[Don_P]

I'm unclear on the fireplace footings and chimney penetration. Also check the ridge support post compression into the support beam and the support beam's capacity on the 54" span in the lower drawing. There will need to be headers over the 72" opening in the upper drawing and the ridge appears to be unsupported. whatever is there will also need to be checked for combined beam and column load at that height.

[UK4X4]

Don,

sorry been off living in a tin shack in venezuela with the wifes family for the last week ! no phones no e-mail - lovely weekend drinking far too much rum - showing my daughter life on basic scale including taking 4 hens and converting them in a soup !

a fires not been chosen yet - so that part is not detailed- but would probably have its own footing
no so worried about frost heave on that as would be physically seperate to the framework if its going to be heavy brick

I used Ilevel Forte software for the cross beam supporting the Ridge post

The calc was done about 10 times as I got used to the software, and checked against the way you demonstrated for standard beam moment till I got roughly the same answers- them moved onto to more technical beam

It includes what type of support materials and the area required- plus the loads for each post

Using half the total possible ridge load inc the 2ft extensions- I put it as a point load at 9ft midway between the two center posts

Then messed with a spread load with those beams supporting a floor at the same time

If I go tight it can be 3(2x10)'s if I wanted to add a loft its 3(2x12)'s only

Or some more LVL's

With the added loft load the center post footings may have to be enlarged to support the extra weight.

[UK4X4]

report from Ilevel software

[Don_P]

Wow, nice software 

[UK4X4]

The only issue I have is the seismic and wind factors

the software lets you set a primary -zone ,wind factor

But accepts manual values from some engineering manual- that I could not locate

I've been messing with it for a week now

The calcs you showed me how to do -basicly match

the point load and spread combined is above my present knowledge level to check

But I messed with the settings and worked out what came out sounding right.

I'll be submitting the reports of the beams with my dwgs to the permit office.

But still have some work to do on the modifications people suggested.

I should be done by the end of the weekend- been messing with adding a central cross beam - but it takes so much load
that 1 big lvl ridge beam may be better

[Don_P]

Are you designing the central crossbeam as a beam with a post at midspan or as a truss?

[UK4X4]

Beam and post

you have'nt shown me the truss calc yet ! and the software I've found to date does not cover that construction....at least not freeware !

actually just ship me those lovely 10X trusses you have laying in your workshop- sure they'll be fine !