Plan Dimensions / Confrontational Contractor
Plan Dimensions / Confrontational Contractor
(OP)
I got a call from a foundation subcontractor asking for dimensions on my foundation plan. I told him that it is not standard practice for the structurals to show dimensions and that he needed to reference the architecturals for all dimensions. My thought is that for me to provide dimensions would be a "Means and Methods" issue. Does anyone agree/disagree? The guy was really rude and confrontational and I'd like to have a very clear response for him.






RE: Plan Dimensions / Confrontational Contractor
Other times the architectural drawing are used early in the life of a project, say to show the Owner what the finished project will look like. Then, despite the usual changes and evolution that any design goes through, the architectural drawings are not updated or revised.
The Contractor has effectively asked you for a drawing interpretation. Based on your response to the question, if the Architect has made any mistakes, it is now your fault. Suggest that you provide the foundation dimensions.
www.SlideRuleEra.net
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
Only time it became an issue was an Architect insisting that dimensions be added... project was changing faster than a...
I ended up by advising him that we would only add dimensions provided by him on a marked up drawing.
Dik
RE: Plan Dimensions / Confrontational Contractor
cnickers, not trying to question what you do, but in my opinion, its a lazy, crazy structural who doesn't provide their own dimensions.
...this is for commercial, larger projects though - for small residential it might not make sense to show all the dimensions.
RE: Plan Dimensions / Confrontational Contractor
Granted I have only been practicing for 7 years, but this is the first time I have been asked for dimensions on the foundation plan for a small residential project. It's important to note that I do provide structural dimensions for elements that I am placing in space.
One issue I am concerned with is providing dimensions to locations of items such as shearwall holdowns. I also feel that if the architecturals clearly show the dimensions of the building's walls, why should I duplicate them on my drawings? Isn't that asking for conflicting dimensions? Say the architect makes some minor tweaks, doesn't think to update me, and the contractor uses my dimensions to layout his foundation. Sure, blame would fall squarely on the architect , but what good does that do? The concrete's already cast.
I think I will provide the contractor the dimensions for footings and not the holdowns, but I will run the drawing through the architect for their approval first.
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
Yes it is asking for conflicting dimensions when both the architect and structural show dimensions. From experience, I always insist on showing dimensions. What if the architect changes something that appears to be minor but from a structural standpoint is huge? I had a case where a column got bumped out one foot either end of a beam. In the commercial arena, it most likely wouldn't be a problem. But in this case, we had strict criteria on beam depth and the deflections increased significantly. Ultimately, the beams had to be stiffened with plate.
Having the dimensions on the plans just creates a little more coordination between you and the architect. It also forces you to have clear communication in your contract and with the architect on the importance of sharing information that changes as the project develops. Make it clear to your clients that changes, while they may be minor can add up and you may have to charge extra for many revisions.
Good luck.
RE: Plan Dimensions / Confrontational Contractor
One thing that we do is require the arch and struc drawings to share the same column grid and column drawing.
This "colgrid.dwg" file is maintained by us (structural) and xref'd into both the architect's and our plans. That way, there is never any conflict between A and S drawings regarding the basic column/grid layout.
Now for cnickers project of a duplex townhome, I would point to a recent project we did that consisted of a lot of wood framed bearing walls. In this case, I have to admit, we didn't dimension to every single wall.
We did have a "colgrid.dwg" file that indicated some important baselines, column lines and other key features that helped tie the project together dimensionally.
So for the townhome I'd say that refering back to the Architect's plans would be OK for all the myriad wall layouts and to supplement that with structural dimensions where needed.
RE: Plan Dimensions / Confrontational Contractor
What happens when there's a 1/2" chamfer at the edge of the slab, at the base of the brick? Architect shows 68'-0" overall, but this is brick-to-brick. The slab should have an extra 1/2" each side, or 68'-1". If I'm the engineer of that foundation, I want my drawings to show 68'-1".
I'm talking about overall foundation dimensions, dimensions to interior grade beams, columns/posts, things like that. If your shear wall details show where to install the holddowns, I'd say that's plenty good enough. Dimensions to every holddown, post base, etc. I would not expect on structural drawings.
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
I suppose in the future, the contractor will just have the BIM model, and will construct the building from that.
Kind of a scary thought really.
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
I think what's important is you show what it takes for a reasonable person to understand your intent, and that you follow the standard of care for your locality.
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
Foundations should be dimensioned such that the contractor can layout the entire foundation just off of the foundation plan (not referring back to architectural or having to calculate dimensions). No need to show all the architectural dimensions but main grid-to-grid and face of concrete dimensions are typically shown.
Then again, "standard practice" is a huge variable depending on your location. I'm in the westcoast United States.
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
Sure, blame would fall squarely on the architect , but what good does that do?"
I'm not sure that's the case... FWIW, I've even had problems when XREFS are used... often no one seems to update things... some offices make sketches independent from the drawings and changes are not carried to the original cad files.
Dik
RE: Plan Dimensions / Confrontational Contractor
Do subs that you work with really build off of your foundation plan?
RE: Plan Dimensions / Confrontational Contractor
That seems to be the point to preparing the drawings. Can't expect the general contractor or the architect to coordinate everything - verifying dimensions often falls to the guy actually doing the work. I don't want the backhoe operator or the grade staker or anybody else to make an incorrect interpretation of the plans, just because he is too lazy to go get the entire roll or to call the architect - who is probably out to lunch...
RE: Plan Dimensions / Confrontational Contractor
What I meant was, don't they build off of the shop drawings, not your structural foundation plan? If they build off of the structural foundation plan, I would say what is the point of the shop drawings.
RE: Plan Dimensions / Confrontational Contractor
RE: Plan Dimensions / Confrontational Contractor
We always dimension everything necessary to build, (aside from things like CL steel to face of brick). As said by others, it may be unnecessary in some cases, but your design is based on certain dimensions.
RE: Plan Dimensions / Confrontational Contractor
Lack of control of dimensions can create unsafe conditions.
RE: Plan Dimensions / Confrontational Contractor
ZCP
www.phoenix-engineer.com