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.
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Plan Dimensions / Confrontational Contractor
- Thread starter cnickers
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SlideRuleEra
Structural
IMHO, relying on the architectural drawings for structural dimensions is a recipe for trouble - I have seen this happen too many times. Foundations (and other structural details) may bear on relationship to the overall architectural "look".
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.
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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.
Typically we ask the architect for a dimensioned basement plan. We let them selected top of wall and top of brick shelf etc...Sometimes this process requires a gentle nudge. We take this plan and create a foundation plan showing all walls, footings, details and dimensions. The contractor does not have a right to be confrontational but does have a right to ask the design team for enough information to proceed in a cost effective manner.
I usually use dimensions but have shown strip and spread footings with a note to the effect that footings should be centred under columns and walls U/N.
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
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
I always show structural dimensions - now granted, these are most always tied in with their plans via Xref's in autocadd - but we also show a lot more dimensions than the architects do.
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.
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.
- Thread starter
- #7
Thank you all for your comments. I should have stated in my original post that the project is a duplex townhome.
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.
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.
There is no single right answer; but the Contractor should not expect more than what is typical local practice. Where I am structural drawings would not normally show dimensions, unless they are important for the performence of the structure (or if there are no Architect's drawings of course).
COEngineeer
Structural
I always put dimensions on my foundation. A lot of time I made the wall thicker (for lateral pressure on the basement wall), add counter fort, add a column in a wall. The architect will not have dimension or coordinate of the pad underneath the column in the wall. How are they suppose to know where to pin point it? I think the contractor should be able to build the house w/o the architectural drawing. I think the architectural drawing is like the icing on the cake.
"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?"
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.
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.
rgerk - I agree fully.
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.
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.
I'm with JAE. How can you not show dimensions on your foundation plan? The architect is showing walls, brick, windows, etc. The extents of the concrete foundation is the engineer's job, based on my experience.
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.
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.
SperlingPE
Structural
I work in the A/E office environment. The A's maintian control of the base plans. The A's dimension the project (grid to grid and any dimensions to bearing walls) as a separate drawing that is xref'd into the structural drawings. Additional dimensions are added as needed by structural. This might be a little different than what is normally done, but it forces both parties to communicate about changes to the plans.
FWIW: In Theory, this issue largely starts to go away as BIM starts to work its way into the system. In theory, you and the architect are now both using the same information model for your work, so there is no chance for a dimensional discrepency.
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.
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.
DaveVikingPE
Structural
I show dimensions on all of my drawings, no matter what they are.
We provide dimensions for the column grids and overall structural dimensions and anything structural that the arch't wouldn't show, cuh as a column. For instance, we show wall length but will not dimension openings. This approach takes coordination with the architect but that's consistent with how we do it around here.
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.
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.
COEngineeer
Structural
There will be mistakes no matter what. If you combine a good architect, engineer, and contractor, the fewer mistakes you will have. The bigger mistakes (dimensions & elevations) should be caught before it is built.
I put dimensions on the foundation plans after confirming with the architect that all dimensions are final. Nothing is final in this business so I ask the architect to let me know any changes if occurring. Also in the structutral general notes, there should be a note requiring the contractor to contact the architect when discrepancies are found, proceed with construction after they are resolved.
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.
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.
whyun has a good point that I usually try to follow: if work is by a subcontractor, put all requirements on just the plan sheets that will be issued to the subcontractor. Foundation subcontractor will not be interested in looking at a set of architectural plans. Just as the electrician couldn't care less about the site civil drawings...
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