NEW TYPE OF DECK SUPPORTS

[CHARLIE VAN FLEET]

GUYS

1968 mounting home in boulder co--$1,000,000 price tag--the decks and upper levels were built in 1998--permits pulled but dn't know if finaled and inspected--what if the rocks move--writing it up to have a structural engineer give it a look--never saw this before--wht do you think


cvf

[Jack Feldmann]

Are those 4x4 posts? Are they over 8' high?

[CHARLIE VAN FLEET]

Are those 4x4 posts? Are they over 8' high?

they are 4 x4 but this was a quick photo because I just deployed radon test today Wednesday is inspection--they only appeared to be about six foot high--but they bare on red rocks--that were flattened out to hold post--more complete look on Wednesday

cvf

[Mark Reinmiller]

If the rocks are sitting on soil I would not approve it. If the rocks are well seated on rocks below it may be fine.

[Jack Feldmann]

Not sure what type of rocks they are sitting on, but I bet the rocks are bigger than any footing they would have put there. I'm guessing the rocks were naturally there, and not brought in and plopped on fill.
What are the post holding up? Is it just a deck?

While I would probably call for an engineer to look at it, my rough guess is the rocks may be strong enough to support the load. A lot depends on what kind of rocks they are, and if we are only seeing the tip of the iceberg if you will (only a portion of the rock is above ground).

You were there, so you are better to make the call because you can see the big picture.

[CHARLIE VAN FLEET]

Not sure what type of rocks they are sitting on, but I bet the rocks are bigger than any footing they would have put there. I'm guessing the rocks were naturally there, and not brought in and plopped on fill.
What are the post holding up? Is it just a deck?

While I would probably call for an engineer to look at it, my rough guess is the rocks may be strong enough to support the load. A lot depends on what kind of rocks they are, and if we are only seeing the tip of the iceberg if you will (only a portion of the rock is above ground).

You were there, so you are better to make the call because you can see the big picture.

jack

think the rocks were not made by God--but ill get more photos at inspection--this property was not nature

[Lon Henderson]

If the rocks are naturally placed "by God", then that deck is probably more solid than on concrete. But, if placed by humans, then I would question their stability. Your photos don't look natural. I suspect they were relocated to accommodate the house foundation. At least, report your suspicions if you think they are not naturally placed and concerns and recommend evaluation from an engineer.

On one hand they survived the massive rain of Sept., 2013, so they are unlikely to move around but if they are just placed on the dirt, that isn't a "best practice".

[Hilary Goss]

they are 4 x4 but this was a quick photo because I just deployed radon test today Wednesday is inspection--they only appeared to be about six foot high--but they bare on red rocks--that were flattened out to hold post--more complete look on Wednesday

cvf

Solid as a Rock. You reported it correctly. H Goss

[Dana Bostick]

I used to run into this all the time on the cabins up at Donner Summit area of the High Sierras. Under the house they would flatten out a small area on top of a granite boulder that had been there for millions of years and use it as the footer for the posts.

This does look like they were "placed" there for the purpose of supporting the deck and for aesthetics.

[Jimmy Roberts]

GUYS

1968 mounting home in boulder co--$1,000,000 price tag--the decks and upper levels were built in 1998--permits pulled but dn't know if finaled and inspected--what if the rocks move--writing it up to have a structural engineer give it a look--never saw this before--wht do you think


cvf
Looks like the deck is supported by a column of weight bearing atmosphere.
The rocks are pretty massive, appear to be several tons each. That roof likely will not produce enough load for the rocks to even know it is there. However, appearance has been known to be deceiving.

[Fred Comb]

GUYS

1968 mounting home in boulder co--$1,000,000 price tag--the decks and upper levels were built in 1998--permits pulled but dn't know if finaled and inspected--what if the rocks move--writing it up to have a structural engineer give it a look--never saw this before--wht do you think


cvf

What is the frost depth in your area? Does the base of the boulder reach that depth? Will the shape of the boulder promote heaving?

[Hilary Goss]

What is the frost depth in your area? Does the base of the boulder reach that depth? Will the shape of the boulder promote heaving?

Often the deck will have potted plants, hot tub or other secondary water source or load added overhead. Wind blown rain, the new owner raking pine or other debris away from the base support soil areas of those rocks. Any erosion man made or nature caused will weaken this installation with no side supports in place for the posts either. I have seen below deck areas become dog kennels for vacation homes or permanent residence. Digging animals, squirrels or dogs can remove support soils quickly add a rain or drainage splash pattern, just as effective. Using this method below the home for foundation support is only somewhat safer, seldom in a seismic area would this be trusted.

[BridgeMan]

I'm an engineer, and would not want my licenses at risk by approving such a deck foundation. Loose boulders have been known to move, regardless of how old they are. One of the columns looks well out-of-plumb already.

[CoronadoBruin]

a PE, preferably a Soils, to sign off on it. I'm not an inspector but I would place a disclaimer in your report suggesting the same thing.

[jbuckhead]

GUYS

1968 mounting home in boulder co--$1,000,000 price tag--the decks and upper levels were built in 1998--permits pulled but dn't know if finaled and inspected--what if the rocks move--writing it up to have a structural engineer give it a look--never saw this before--wht do you think


cvf
Without documented approval and sign off what else can you do other than recommend further evaluation.it doesn't look right to me. Erosion would be another concern of mine.

[John Kogel]

The post out of plumb needs repair certainly.

If there is any danger of erosion down the bank behind those boulders, it is a concern. A stacked boulder retaining wall is very stable if built right, better than concrete. But you want to inspect the slope or wall behind those boulders.

[Lloyd Goldrick]

[QUOTE=CHARLIE VAN FLEET;253234]GUYS

1968 mounting home in boulder co--$1,000,000 price tag--the decks and upper levels were built in 1998--permits pulled but dn't know if finaled and inspected--what if the rocks move--writing it up to have a structural engineer give it a look--never saw this before--wht do you think


cvf So you are saying the columns have been on the boulders since '98? It does not look like any movement has taken place. My guess is if the boulders start moving so will the rest of the mountain, but having an engineer look at it will certainly be prudent.

[Scott Patterson]

It looks like the boulders were "plopped" or placed and are not natural to their current location. I would also bet the area might have fill to level it out and the boulders are also acting as a retaining wall of sorts. But this is all SWAG from a couple of photos.

[CHARLIE VAN FLEET]

GUYS

did inspection today on that mountain deck house--looks like they are Gods installed rocks--but stil scary to me--two of the post have vertical cracks--so recommended evalution by structural engineer --here are some more photos

cvf

[Jerry Peck]

From the new angle, the posts appear to be bearing on the rocks well beyond the center or rotation of the elongated shaped rocks.

If Mother Nature placed the rocks there, maybe she needs to get a real engineer on board with her ... or create the rocks with warning labels "Do Not use the pointy top of the rocks as structural support for future structures". :)

[Randy West]

I was a contractor in the Rockies west of Denver for many years, Jefferson County not Boulder County. But I built many decks (and sometimes part of the home) supported on the granite like this deck. They were all planned, permitted, inspected and approved. I see it here in AZ too. It is a little unusual to have the bottom of the post on an 'overhang'. But it does not look like those boulders have moved, and it does not look like the deck has settled/moved. If that granite 'breaks', the house is likely on its way down the mountain anyway. If everything else on the deck construction was good (eg lag bolts, joist hangers, post bases, etc.) I would not recommend an engineer.

Some replies say "everything looks OK but recommend engineer". Why? If I can't say exactly what looks 'wrong' I am not recommending an engineer. I would recommend my clients (assuming they are the buyers) ask the sellers for permits. The deck was added after the home was built. If the deck was engineered, permitted, inspected and approved and the sellers have the paperwork why would you need an engineer? And wouldn't you feel kind of silly when the seller presents all the paperwork and your clients ask you why they need an engineer?

If the deck was not permitted then there are potential problems even if it is well built.

[kenny martin]

I'm not seeing post cap connections where the supports rest on the 4x4s? And also there is cantilevered deck beyond the posts over the drop off as seen in the second pic from the first set of photos that may need angle bracing back to the posts? Also it appears at least one post is sitting on top of the walk edging unsecured? :/ I would recommend an Engineer but that's just the way I see it..

[John Kogel]

If it was built right in the first place we would have nothing to discuss here. With the price tag on this house, that deck could be sitting on steel archways. Why would anyone argue that it is good enough on those flimsy 4X4's with no bracing, cock-eyed post, missing brackets etc?

It hasn't collapsed yet but maybe it hasn't been tested yet.
I'm talking a Billy Stevens Hot Tub party, 30 guests jiving to Elvis and shooting their guns off in wild celebration. :D

[JC Warner]

Sorry, skidding a little off topic, but regarding the downspouts, I don't see any straps or brackets. Did someone just screw or nail right through them? It is hard to see from here.
Thanks.

[Thom Huggett]

I think you get an evaluation by a Geotechnical Engineer (Registered Civil Engineer specializing in soils) to evaluate the boulders as well as the overall stability of the cliff. Also, there should be some lateral bracing for the posts and support beams. Looks pretty scary to me, too!

[Bruce Low]

Are the joists cantelevered and the posts (simply) cosmetic?

[kenny martin]

Not cosmetic.. the deck was not constructed properly and is not secured/braced in required locations. I would be very interested to see how it is attached to the home also and if the bolts are protected from water with proper flashings. Once again, an Engineer would be my recommendation.

[ROBERT YOUNG]

Many forces in addition to gravity can affect a deck’s ability to remain stable. I see no anti sway bracing.

Remember, high winds may likely cause uplift plus top heavy decks can shifting or rack. Both of which cause tremendous stress and possible failures.

Utilizing 6x6 structural posts have twice the resistance to sway than 4x4’s.

Tall decks such as this are much more susceptible to these unbalancing forces.

No anti sway. Buring the posts would have contributed to stability.

[CHARLIE VAN FLEET]

buyer had structural engineer out--he said it was good--but recommend bigger stirrups on base of two posts--told client to get it in writing--I still don't like it but I did my job--over and above

cvf

[Mark Reinmiller]

Many forces in addition to gravity can affect a deck’s ability to remain stable. I see no anti sway bracing.

Remember, high winds may likely cause uplift plus top heavy decks can shifting or rack. Both of which cause tremendous stress and possible failures.

Utilizing 6x6 structural posts have twice the resistance to sway than 4x4’s.

Tall decks such as this are much more susceptible to these unbalancing forces.

No anti sway. Buring the posts would have contributed to stability.

Unless the columns are set in concrete in the ground they really do not provide any significant resistance to lateral movement. Some form of diagonal bracing is typically needed.

[CHARLIE VAN FLEET]

done here

[ROBERT YOUNG]

Unless the columns are set in concrete in the ground they really do not provide any significant resistance to lateral movement. Some form of diagonal bracing is typically needed.
I concur. With concrete.

[Raymond Wand]

Those 4x4s appear to have post saddles installed, and the rebar portion is drilled into the rock. Do you still feel they need concrete and lateral stability?

Typically up in cottage country this is how deck posts are mounted into the exposed granite of the Canadian Shield with post saddles.

[kenny martin]

Those 4x4s appear to have post saddles installed, and the rebar portion is drilled into the rock. Do you still feel they need concrete and lateral stability?

Typically up in cottage country this is how deck posts are mounted into the exposed granite of the Canadian Shield with post saddles.
It does not appear all are but it is possible there is something there I am not seeing. The ones on the boulders appear fine but I make no opinion definitively because I'm not there to see the hill beneath although I would recommend some diagonal bracing. It does appear however there are standard post bases utilized on others.

[Mark Reinmiller]

Those 4x4s appear to have post saddles installed, and the rebar portion is drilled into the rock. Do you still feel they need concrete and lateral stability?

Typically up in cottage country this is how deck posts are mounted into the exposed granite of the Canadian Shield with post saddles.

Post saddles and rebar do not prevent the deck from swaying. You really cannot properly transfer bending moments through those types of connections. Diagonal bracing on columns or at the underside of the deck would typically be needed.

[CHARLIE VAN FLEET]

guys--the structural engineer signed off on this deck--why are we still talking about it--let it go--it is in the hands of the engineers

cvf


OVER AND OUT

[Raymond Wand]

Thanks Mark.

[Fred Sweezer Sr]

This is not a new type post connection it is an "improper post to footing connection", post to footing connection should protect the post from slipping or moving, proper footings are not in that picture, referring to a structural Engineer is appropriate.

[Mark Reinmiller]

guys--the structural engineer signed off on this deck--why are we still talking about it--let it go--it is in the hands of the engineers

cvf


OVER AND OUT

For educational purposes, when inspectors questions things or provide information that I think is incorrect, I continue to respond. Signing off on something can mean many different things. I am a Structural Engineer and don't always agree with things other SEs say. I did not really look at lateral stability issues with that deck, rather I was responding to notion that the size of the columns or methods of connection have little to do with lateral stability.

Sometimes we beat dead horses here, but often there is something to be learned along the way.