sloped insulation

[sfaust]

Is there any way in Revit to tell it to create a flat roof but to slope the insulation? Right now I am just editing the cut profile in section, but it would be nice if a roof was smart enough to let you model the actual sloping insulation and give spot elevations etc. Maybe this should go in the wishlist section, but I put it here hoping that it might exist...

while I'm at it, it would be good to be able to add a cant to an edge just like a thickened floor slab edge...

[gregcashen]

There is no way to do this within the existing roof tool...you will have to do it with an in-place family (which, frankly, sounds like a PIA!) We have requested horizontally compound roofs for a while...some of us have, anyway...

[sfaust]

hmmm... that's what I figured, just thought I'd check. Put my vote on the wish list then!

in place family is probably harder than editing a cut profile...

thanks for the input

[sbrown]

Why not just use 2 roofs one for structure one for insulation, then join them together. I find I need two roofs for many applications, ie spanish tile that overhangs past the structure. Just make sure you create both roofs with the pick walls tool and they will move as you want them to.

[christopher.zoog51272]

Just make sure you create both roofs with the pick walls tool and they will move as you want them to.

Good point, you can't just copy the first roof up a few inches and maintain constraints

[rodneyf]

Hey Guys,
There is a new family on the Revit web library that has a Tapered Rigid Insulation under Detail Components. If that is what you are looking for.

HTH,

[sfaust]

I know, and I have been using that for details, but what I wanted was for it to actually model the roof, so I could use it as a study tool to input the slopes that i want and make sure that I have enough parapet, etc. with the slope I need. This would also make sure that the tapered insulation is shown correctly in order to figure out flashing, etc. It just another way that Revit could save coordination and drawing errors.

steve

[Archman]

I know, and I have been using that for details, but what I wanted was for it to actually model the roof, so I could use it as a study tool to input the slopes that i want and make sure that I have enough parapet, etc. with the slope I need. This would also make sure that the tapered insulation is shown correctly in order to figure out flashing, etc. It just another way that Revit could save coordination and drawing errors.


Man, Do I ever agree with you on this one! Had this very issue come up on my latest project. The designer wanted the lowest pssible parapet. It would have been nice if Revit could have helped me with that.

[sbrown]

Revit can help with that, just model the crickets as sep roof pieces, you can model each one then join geometry. I don't know how people figured them out before revit.

[tatlin]

Scott,


Revit can help with that, just model the crickets as sep roof pieces, you can model each one then join geometry. I don't know how people figured them out before revit.

Are you sloping the structure or just tapering the insulation? If the latter, it sounds like you have a flat main roof and then build up the insulation on top using individual footprint roofs. Then you use join geometry to clean up the overlap? What happens when you need to move the low point around or do other edits?

Instead of doing this additively, you might want to try subtracting geometry instead.

Have you tried creating a thicker main roof (with say a 10" rigid insul layer) and then cutting out the crickets with voids? We actually have used roof-based cricket families inhouse to do this. Just a void blend with some instance parameters. This way you place them in your main roof and stretch them to whatever size you need.

You can even constrain the low points to actual roof drain families if you wanted, or build the void into the roof drain family. This sounds a lot more associative in general.



General (leading) questions:

How important is the case for people? We all know that no roof is really 'flat', but how much does that matter in the grand scheme of things? Do you really need to model it or could you just draw it in you roof plan?

Do you spend a lot of time modifying 'flat' roofs and even 'flat' concrete foor slabs to get drainage right? How often do you slope the structure vs tapering insulation? (That is, keeping both faces of the roof parallel vs just sloping the top face)

What kinds of views do you want to see this in? Just the roof plan? Does is matter that the sections and details have the correct slope? Are there any other hosts you'd like to 'tweak' faces of?

How important is this in the grand scheme of things?

thanks,

[Steve_Stafford]

If you consider all the trades involved I think it IS important to be able to model true slope when talking about flat roofs. A flat roof may "look" like it offers enough clearance in section for all the business inside but when sloping steel is factored you find otherwise.

Conversely as Archman was saying, it would be nice to be able to better predict what your roof edges will need to be to accomodate the required slope rather than compromise on educated guesses and hoping the contractor won't wind up too thin overall.

It's helpful info to see how we can achieve this now, but I think you would agree that it should/could be "easier".

[gregcashen]

I had a request to show the 1/4" per foot slope on the deck of a house I just finished and this would have been nice. I could see it working like the roof slope tool in general. Just draw a slope line, give it an elevation off the main level or a slope% and it would figure the rest out.

[cgrover]

I feel this would be very important. I do a lot of commercial projects with "flat" roofs and to be able to model the roof/insulation slopes would be helpful throughout the design process.

thanks,
grover

PS: Does anyone have the link to the Tapered insulation on the Revit website as referred to in an earlier post.

[sfaust]

I think it would be a very nice thing to have for roofs. We also do a fair amount of commercial work & school work, which both tend to use flat roofs. I think it would be much more important to have this ability for roof slabs than for floor slabs for a couple reasons:

1- a roof is never actually flat, a floor slab is usually flat in most places.

2- roofs are more complex and usually have many different slopes that go to different drains where a floor usually would only have one area sloped toward one drain. This is much easier to figure out than a roof.

My opinion is short is: no, it's not absolutely necessary, but gee it would sure be helpfull!!

[sfaust]

I don't know where the tapered insulation is on the Revit site, but here it is:

[Scott Hopkins]

I also strongly agree that the ability to easily and accurately show flat roofs would be extremely valuable. 1/4"/ft. over 50 feet adds up vertically pretty fast. Typically there are so many coordination issues involved (structural clearances, zoning height limitations, drainage issues, parapet heights, HVAC screening, etc.) that is essential to draw sloping roofs in section. Improved tools in this area would be greatly appreciated. Looking back on the flat roof projects I have done, it is about 50/50 between using the building’s structure to create the slopes versus using tapered insulation.

[Scott D Davis]

I really like the idea of placing a roof drain, and using a parameter to set the elevation of the drain, and then the roof would automatically slope to it at a specified slope.

[sfaust]

that sounds fabulous. As long as you had control over how it sloped, that would be wonderful...

[sbrown]

Here is my process.

1. schematic/dd - sloping compound roof including structure, ie. 1 layer epdm, 3" rigid, 1 1/2" deck, 2' steel structure. Yes slope structure, may need to be multiple peices of roof depending on how your construction is.

2. dd/cd. get rid of structure and place true structural elements.
add crickets as roof as required, many of them are just linework on the roof plan join geometry where required or just do a filled region once figured out.

It would be great to make this more automatic, but I've had great success with this approach.

[bclarch]

Matt,

Thanks for asking. Here goes.



General (leading) questions:

How important is the case for people? We all know that no roof is really 'flat', but how much does that matter in the grand scheme of things? Do you really need to model it or could you just draw it in you roof plan?

It is very important to be able to show correct slopes in sections and details not just plan. This is a very common source of errors in drawing sets. When the effects of roof slope are not considered or improperly calculated it can cause problems with parapet flashing details, expansion joint details, blocking details at equipment supports, heights of roof curbs at skylights and HVAC equipment, details @ roof/wall intersections, details @ roof height transtions, etc.


Do you spend a lot of time modifying 'flat' roofs and even 'flat' concrete foor slabs to get drainage right?

Hard to quantify how much time, but enough that it would be worthwhile to have a better tool to do it.


How often do you slope the structure vs tapering insulation? (That is, keeping both faces of the roof parallel vs just sloping the top face)

In my experience, when the building is a rectangular box it is more common to slope the structure. Once the building takes on a more unique shape the slope is usually handled by building up the insulation. On very rare occasions I have seen both the structure and insulation sloped.


What kinds of views do you want to see this in? Just the roof plan? Does is matter that the sections and details have the correct slope?

See response to item one above.


Are there any other hosts you'd like to 'tweak' faces of?

Mostly roofs and floors.


How important is this in the grand scheme of things?

Very. Again, its a big source of coordination errors.

As far as implementation goes, most commercial roof drains are installed in a four-sided, sloped sump. If there were slope arrows associated with each side of the sump which would modify the top surface of the adjacent roof area, that would probably handle the majority of situations. The top of the drain could have a setting for "height of rim above deck" or something similar. Sump size and slope could be type specific parameters.


I think that most crickets and saddles could be handled easily enough as footprint roofs. It would be nice if they could be made to recognize the upper surface of the roof and adjust their height to sit on that surface.

Thanks again for seeking our input.

[gregcashen]

I really like the idea of placing a roof drain, and using a parameter to set the elevation of the drain, and then the roof would automatically slope to it at a specified slope.

I was sitting in a class today thinking about this problem, and a solution (short term) occurred to me. Scott, make a roof based family that consists of...oh forget it. Here it is. Rough right now, but play with it and see what you can come up with.

[Scott D Davis]

Greg!

So ironic....I did almost the exact same thing last night brainstorming this roof drain thing! I created a roof based generic model, that had a solid cylinder respresenting the drain, and a void blend used to cut the roof! Seemed to work pretty well. I need to mess with it some more. It would be nice to Tab over the shape handles, and be able to stretch/align the void with the roof it is set on.

Another thing that we need to be able to control, is slope, rather than 'top and bottom' elevation. Not sure how to pull this off yet.

Good start! Another idea would be a new kind of Slope Arrow, as someoneone mentioned above. This new slope arrow would control only the top surface of a roof or floor. Then if we had the ability to build a family WITH slope arrows built in, you could place it in a model, and then set the parameters for the slope to update the roof.

[PeterJ]

Or perhaps be able to apply an 'always vertical' tag to selected items in families that might be hosted by a sloping element, but leave the remainder to follw the host geometry....

[Scott Hopkins]

For anyone that wants it - I tweaked the rigid insulation detail component so that it is still adjustable but has a constant slope of 1/4" per foot. It seemed a lot more useful that way, at least for non-metric users.

[Scott D Davis]

here's my attempt of a roof drain with a void-blend to cut the host roof. It has instance paramenters, which allow you to 'tab' to a shape handle to stretch the cut over your roof, and also to position the drain within the roof. Might need a little more tweaking, but the concept is there.

[gregcashen]

Draggable handles can be acheived by using invisible model line sinstead of ref planes to constrain the width. Slope can be made as a formula parameter with the following formula [code:1:535ae4e235]Slope% = (Vertical Offset/(Length/2))*100[/code:1:535ae4e235]

[gregcashen]

Here is my latest attempt. It is hard to know what parameters should be type and instance. Play with it and let me know what you think...

[PeterJ]

Slope can be made as a formula parameter with the following formula [code:1:b8faae25da]Slope% = (Vertical Offset/(Length/2))*100[/code:1:b8faae25da]

We use angles here generally and I am not familiar with slope. is a 45 degree angle a 50% slope? That looks to be the case from your formula.

[gregcashen]

Slope is literally height divided by length...so in this case, the "height" is the vertical offset (or depth of the drain) and the length is actually 1/2 the total length of the family because it slope from both directions toward the center.

In short, a 45° angle would be a 100% slope. 5'/5' = 1.00 = 100%

So a 1/4" / foot slope would be 1/4"/12" = 1/48 = about 2% slope, which is pretty typical for decks and other surfaces in the states.

[PeterJ]

Thanks

[Vincent Valentijn]

Tatlin..

Overall I think it's quite simple.. the closer the Revit Model comes to the reality of a building, the less extra work we (or subcontractors) need to do to create construction drawings.
So if you guys can come up with a simple way to draw real sloped floors and/or tapered (slope in insulation) YES PLEASE!! :D make our lives easier ;).

[bclarch]

I think that the interest that this topic has generated is testament to the fact that there is a strong need for this functionality. And Matt, if we could have it in 6.1 that would be great. :wink: :D

[ajayholland]

I have experimented with blended solids to create the warped slabs and roof decks that typically occur in our projects.

For an anticipated model of a new parking structure, I wanted to avoid the use of in-place families, and began to develop a “blended solid” family for the model, with instance parameters for the elevation at each corner.

I’ve created two types: one with parameters to place the slab below its reference level, the second to place the slab above. The blend depth is in the short direction, so the slab length will adjust by alignment; the width (blend depth) must be specified by instance parameter. The slab thickness is available as a type parameter.

Since floors and roofs are not available categories, I assigned the families to structural framing. When placed as a model component, the slab will report the spot elevations of its corners (including 3d), but is not available for wall attachment. Experimenting further, I placed the component inside an in-place family with the floor category – in this case walls will attach to the blended slab, but spot elevations do not behave correctly.

I’ve attached the sample files.

-AJH

http://www.zoogdesign.com/forums/phpBB2/download.php?id=1595

[gregcashen]

[quote:aa1d439a77="gregcashen"]Slope can be made as a formula parameter with the following formula [code:1:aa1d439a77]Slope% = (Vertical Offset/(Length/2))*100[/code:1:aa1d439a77]

We use angles here generally and I am not familiar with slope. is a 45 degree angle a 50% slope? That looks to be the case from your formula.[/quote:aa1d439a77]

Okay, I just learned in a surveying class I am taking that there is a difference in the way slopes are interpreted in Metric and Imperial...

In Imperial, if you said that a grade had a 2:1 slope, that would mean that it rose 1' for every 2' horizontal.

In Metric, it means that the slope rises 2' for every 1' horizontal.

May have caused confision, and since it was fresh in my mind, I thought I'd share :roll: