Existing Foundation - Start with foundation level?

[ERousculp]

Two Questions:

1) Is it ever advisable to start a model with the foundation?  We are building a new house on an existing foundation so the first floor should really be referenced from the foundation.  The foundation is partial basement and crawl space with a 24" drop to another crawl space and a 3" drop from that to the garage floor.  The garage is also existing and has block walls (it will be attached).

 

I have created one plan that is only the foundation and garage (garage with 101" walls above the pad) but haven't tried to add the first floor.  Am I headed for disaster?  The thing I like about this is that the foundation is exactly the correct dimensions. 

 

I have also created the first floor plan (with multiple floor heights) and derived the foundation.  A suppose I can stay away from auto rebuilds and just make my modifications. The derived foundation is pretty funky with what appears to be off-set walls in certain places.

 

2)   Is it ok to make the block garage walls part of the foundation level?

[DavidJPotter]

 

1) Is it ever advisable to start a model with the foundation?

No

 

This software is designed to draw the first floor, then foundation, then upper floors, if any.

 

I have never drawn a foundation first but I suppose there is nothing wrong with doing so.

 

My advice is to study first the free video tutorials that are provided with the program (Help-Tutorial videos) and then read the section in the Reference Manual on "Getting Started", then the section about "Foundation Defaults".

 

Using a tool that you have not yet fully studied and practiced with (lots of people do this) is inefficient and productive of learning how to fail instead of succeed.

 

DJP

[Kbird1]

It's not usually advised but some do it ,such as in the case of Walkout basements...... but HD Titles only allow 3 floors plus an attic so that method may not work for all.

 

but the foundation walls when built will align with the Main Layer (usually framing unless changed) of the 1st floor walls , so as long as you have your wall layers setup right and the Dimensions set to indicate off the right layer (Main) when you build the 1st floor the basement will auto build the correct size, and if needed you can always resize the main floor slightly so the basement is correct if needed.

 

So followup links on Walk-Outs for the technique and whys etc:

 

https://hometalk.chiefarchitect.com/index.php?/topic/63-walk-out-basements/

 

https://forums.chiefarchitect.com/index.php?/topic/1066-walkout-basement-stuff/

 

M.

[Elovia]

Welcome to the forum.

 

I don't see why a person couldn't start with the foundation first, but that just means you'd have to pay extra close attention to details before you otherwise might have to in a standard "first floor then foundation" build.  You would need to ensure auto foundation tools are disabled, and make heavy use of the reference display and wall alignment tools.  You may encounter unintended software behavior if your foundation is on the first floor of your plan ... that is, if the software is looking for foundation information on the foundation layer.

 

That said, I'd encourage you to build (or rebuild) your foundation on the foundation layer and then build up from there.  Just start with a blank first floor, and then build a blank foundation floor.

 

 

... but HD Titles only allow 3 floors plus an attic so that method may not work for all.

 

Just a small point of clarification:  HD Architectural 2015 and HD Pro 2015 both allow up to 5 floors (the rest allow up to 3).

[Kbird1]

A new feature in 2015 I guess ... It was 5 floors total previously I think ....   ie  BM_1_2_3 Attic. 

 

thanks for the heads up....

 

M.

[ERousculp]

Thanks for the replies.  I'll get back to the model soon and keep going with:

1)  the first floor generating the foundation

2)  modifying the 1st floor until the auto generated foundation walls are the exact dimension

3)  turning off auto-regenerate and manually add the rest of the walls to the foundation

4)  set the foundation characteristics room by room

 

What does anybody think about the garage walls?  It is block and could be generated in the foundation level.  This would mean having a doorway from the garage (foundation level) into the mudroom (1st floor).  On one hand it makes sense since the garage is block.  On the other I could see how it would mess up the programs auto-configurator logic.   Also, a roof would be placed directly on foundation walls.  As opposed to spending a lot of time running down the wrong path... I will go with the normal method, but I was wondering if anyone had tried it before?

[Elovia]

Floors are not necessarily equivalent to elevation, although many homes are built with all rooms on a given Floor at the same elevation.  A good analogy might be to think of your model as though it were drawn on pages in a book, with model components shown on one page that are directly above the model components shown on the preceeding page, but the elevation of any room on that page may be different from other rooms also on that same page.  It is quite possible to have, for example, a garage slab that is several feet lower than the flooring of other rooms on the same Floor of the model.  The room defaults establish the elevation on which a newly created room will be placed, but that doesn't prevent you from manually changing the elevation of the flooring surface as long as you keep in mind how that change would affect other portions of the model directly above and below the room.

 

Trouble occurs when changes to one floor have unintended consequences to model components on another floor.  Similarly, stair behavior changes significantly depending on if you're connecting two different Floors, or two different elevations on the same Floor.

 

Good luck.

[Kbird1]

Have a look in the KB for the tutorial on Split Level Homes , it should give you some ideas to work with.

 

As Elovia said , no reason floor one Rooms can't be 0" Floor height © in DBX and the "Garage room" on Floor 1 to have a floor height © of -24" for eg.

which may mean the ceiling height in the garage is 10ft not 8ft to keep the second floor all on one plane/level , the Split level Tut. will help you sort that out.

 

M.