estimating practices

[SenecaDesignLLC]

how does everyone deliver quantity data?

is it just in Archicad?

do you use an estimator?

how long does it take for someone to quantify a plan?

i realize these are super generic, but im just trying to get a feel for how much time is spent doing these things.

my current template allows me to quantify everything in a plan in minutes. so i want to find out how others achieve their estimating goals.

[jl_lt]

it depends on the client, as some need extreme accuracy. In our case, we have found out, that once we had an historical list of real costs vs budgeted cost, getting to that 5-10% of accuracy is just not worth the effort, as we can approximate the final cost in much simpler ways.

[mthd]

Yes you definitely have to find the balance and as long as you have a dollar value to cover it, you should be ok.

That all comes with experience as you have found out. Otherwise you spend too much time obsessing over details that can only be determined once it’s built.

Every trade has it’s wastage allowances as well and that can vary from 10% to 20% or so depending on what you are calculating. Concrete ground slabs and brick walls are at the high end.

Even if I measured all the sticks of timber I would still allow at least 10% or more depending on how complicated the timber frame is.

It all comes with feedback from the builder.

Some specialized trades are best given out for tenders as well. I liked to get the HVAC and plumbers to give a direct quote as well.

You got to be on the ball with this type of work.

The bigger the project the more you will need experience.

I am just experienced with houses or low rise construction. It’s a very different ball game for high rise construction or shopping center developments.

It’s better to ask a quantity surveyor who is experienced in the much larger construction projects for a system.

There are many estimating packages out there as well that are good to use with any CAD/BIM system that you may use.

[Rick Thompson]

Would it be possible to see an example of your take offs?  I am curious as to the detail level breakdown (number of studs, lineal feet rake mould etc). I believe from earlier threads you do not use the old Listing functions, which I am still use since the old way does allow a more detailed list in many ways (as confirmed by tech support and others).  My work is a bit different in that my list are not tied to current cost but sent out as an Excel file so easily plugged into.  I can pull a list in 15 min or so.  The only issue is I have to check some links (composites to property objects) as they occasionally break with updates and needs to be reset manually.  I'd appreciate knowing your detail level.

[mthd]

Hi Rick, in the past I used Chief Architect for drawing my framing layouts for estimating because of it’s automatic framing capabilities and it being fast and quite accurate.

Before that I would put a photo copy of the floor plan on the drawing board and drew lines representing the stud positions and other framing elements. Of course I would start with the roof and work down to the ceiling then walls then the floor frame because that’s how the transfer of loads will occur. Similar with a two story house, start from the top and work down. So I would have a separate framing plan for each part of the house. Roof, Ceiling, walls, floor. Or slab and footings for a monolithic slab on ground house. I would also have a roof sheet drawing to set out the roofing elements. Then a roof purlin layout, even a plumbing and electrical layout. The more you can see with your drawings the more accurate you will be. Then taking off the dry wall, I learned that from the dry wall contractors. Same for painting, plumbing & electrical.

Now I draw my framing plans with Archicad (Without Archiframe) but I am not doing any take offs anymore. I have tried a couple estimating jobs with drawing Archicad framing plans but I am much faster with Chief Architect. I preferred using Archicad for my working drawings as I do now.

I can provide you a link on to how they use Chief Architect for automatic framing ? I am not the only one who used both Chief Architect and Archicad. If you live in the USA and you do many residential houses then Chief Architect is worth a look, it’s very easy to use as well.

But you might also look at using Archiframe as well, if it’s not too expensive in your part of the world ? I think it costs the same value of another Archicad license down here ?

My spread sheets are confidential to each building contractor that I did work for.

All good fun if you have the capacity to do those jobs as well.

Here is a link to framing in Chief Architect below. Of course you should design according to the timber framing code in your part of the world. With roof trusses I would get the manufacturer to design them and send me a DWG file. My final drawings are subject to engineering certification and construction supervisors inspection as well a local authority approval. Everything has to be checked along the way. My first job was to design timber truss framing with a Bostich framing system program in the late 80,s after doing a Building Technology course. Then I worked for a home building company as a quantity surveyor, draftsman and sales personnel. Then I went out on my own, I also did an Architectural Technology course to help me further with my home design skills.

https://www.chiefarchitect.com/videos/playlists/93/framing.html

I did supply a full timber order list when doing take offs. That list will include all the framing members including second fix timber the doors the hinges the screws the nails and any other hardware needed to complete the job. Schedules in the CAD program come in handy with other materials that need to be taken off.

If you have been able to set up your Archicad template to accommodate a full materials list take off, then that’s a very good thing. I personally haven’t done that with Archicad yet but it is not that difficult when you know what you need to do to get a fairly accurate costing of your project. 

As to level of detail, I will do the wind bracing and tie down calculations according to the timber framing code. Then I will have the engineers go over it to certify it. The engineers will design the footings and floor slab and any framing or steel members etc that are not covered by the timber framing code. 

Right now I don’t do any take offs anymore and it’s been over a dozen years since my last estimating job. CAD programs are now more developed and can do the job more fully with or without add ons.

The Archicad roof wizard is a good tool to design the roof framing with and I have used it a couple of times in the past. 3D representation of framing elements is more developed these days and can be used with Archiframe if you would like to go down to a finer level of detail.

My personal opinion would be to use the Pryda framing system or any other engineering timber framing software that does the complete job including the trusses and all the connections bracing etc etc etc. If you want to get down to the finished level of detail ? 

I am not familiar with how Revit is used for engineering the structure but others are and that’s why they interact with it for multi story construction. That’s a very different ball game.

I’m just happy to do design modeling before I am fully retired lol.

[Rick Thompson]

Thanks for taking the time for your detailed reply.  I have been aware of Chief Architects abilities for take-offs with frustrations that GS can't achieve anything close, at least as easy.  But, it's geared for residential work only, so that's a huge difference.  The framing part with AC works for me after the initial set up years ago.  I added all the standard cut lumber sizes (2x10x10, 2x10x10pt etc) to the data base with corresponding Property Objects.  So I can make framing plans pretty fast via multiply/drag objects which are linked to the Property Objects via the ID and scheduled easily.. so that part is taken care of.  I suppose I cheat a bit with studs but I was taught the standard estimating is (was) based on one stud per 1' wall which comes pretty close to a 16" oc wall plus jacks and corners. It's easy to add plate material etc.  I actually am fine with what AC can do, but they have thrown the baby out with the bath water, in my opinion by not keeping it running.  Weird that the guide is still featured in the Help menu. Tech support has bumped the issue up, but I am not holding my breath.  I had sent a pla file w/ my support library files to them as requested.  The last tech repose was, and not  encouraging at all >>>  "I hadn't forgot about you, when I have spare time I have been testing properties and expressions along with the custom project info that can be queried to see what kind of reporting I can get out that might resemble the listing options.  Progress has be slow but I'll continue when I can. I'll put this case on hold so it doesn't pester you with automated reminder emails. If I'm able to derive data from your model that gets a bit closer to what you already exported via lists, I'll be in touch."  On the phone he was less encouraging as to using Properties/Expressions to pull it off, especially considering the amount of work involved.

[mthd]

That’s not cheating when you know what your total stud count will be after you have added in your allowances.

Experience is they key with Archicad in being set up for quantity take off of any sort. We usually find a way around to get the job done eventually ?

There are timber and steel frame engineering applications out there that could help with finalizing of the work to certification standards.

I don’t like having to start from scratch and I would prefer to take my 3D framing model into an engineering app where possible and it not being too expensive. I have traditionally done that via 2D dwg transfer back and forth with the framing manufacturer.

In Australia we are allowed to design timber framing for houses that are deemed to satisfy in our timber framing code. Anything outside of that and it has to be done by a certified engineer. I do it because I started out as a timber framing manufacturing employee for our family company and I am familiar with designing timber framed houses  and doing a complete take off for them.

I am not obligated to do that sort of work for my type of design clients. I have had many Builder clients in the past who wanted me to do their timber framing plans for them.

[Holger Kreienbrink]

Let me add some practical ways as we in GS Germany have made a huge test on that. Archicad provides everything you need for a proper QTO.

1. You need to model correctly. For that we have created a modeling guideline. That means that some things have to be modeled in another way as you might think. But the model will return proper plans and a proper model for QTO:
The modeling guideline is here: https://openbim.Graphisoft.de/open-bim-funktioniert/#modellierungsrichtlinie
Sorry it is in german but it might give you a hint as it contains a lot of drawings.

2. in your project you can define calcualtion rules for Building Materials. So that in the end you can define if you want gross, net or conditional values. Conditional values are often used in manual calculation methods (where people ignore holes/voids smaller than xy m2)

3. Then the magic comes in:
We are mainly using IFC export. Cause in the IFC you will get all single skins with their areas and volumes (net, gros and conditional). So you need a software which will read this IFC file. There are a lot in Germany, but also international ones like RIB iTWO or Bexel Manager can handle these files. Inside these programs one can filter: example: walls, salbs, etc etc, internal, external, load bearing etc etc.. -> so at the end you will get all quantities out of your model.

If it is not model (explicit quantity) then use another value(s) to calcualte it (implicit quantity): example: skirting board comes from room circumference minus door width)

These kind of programs can handle prices. At the end you need to multiply prices with area or volume or piece.
Here are some example: https://openbim.Graphisoft.de/bim-webinare/#kosten (sorry german, but try to use the subtitles)

4. If you are using the most expensive software in the building industry (Excel) and not a proper QTO software: go and use the component listings in Archicad. They will return the same values as you have in IFC. But then you will need to maintain your own prices. And that is a huge task.

[mthd]

How to get started and not be overwhelmed by the tasks involved with just using Archicad ?

Please watch this official video on the roof wizard for a conventional roof frame first. It’s from AC17 and hasn’t been updated since then but this is a good start for timber framing right inside Archicad.

If you can do this then you can take the next step by starting a truss roof with the truss library.

https://youtu.be/mTQTuRBhWKU

Please use your span tables and code in your country if they allow you to design the framing member sizes and grades without being a qualified engineer ?

After this step you will need to create wall framing right inside Archicad with the help of the wall framing 2D object. I count my studs from the plan and then enter them to my take off list.

This video is old but it shows how you show the position of 2D studs in your walls. He has a 4 stud junction at his wall but 2 stud junctions can be used in many circumstances depending on the load being carried. Please consult your timber framing code in your land.

https://youtu.be/DcuIjDV8lM0

I am sure we can create 3D framing manually right inside Archicad but if you can find a way to do it automatically then that’s cool.

If anyone knows if the 2D framing object can be reported to the quantities right Archicad automatically, please show us how to do so ?

After this step you need to design the wall bracing units for the wind loads of your particular building site

If you give up here and want to leave that to your engineers or timber framing manufacturer then please do so. It’s not for the faint hearted lol.

If you live in New Zealand then there is Cad Image tool for wall frame bracing.

https://cadimage.zendesk.com/hc/en-us/articles/360000546816-Overview-of-the-Cadimage-Bracing-Tool

For how we design wall bracing in Australia please see this video from Pryda A&NZ. This company is global under ITW and has engineering software for timber framing design. This would be my preferred method of design if I could afford the software ? If not I hope I can share an Archicad 3D IFC model with them and other engineered timber framing manufacturing companies ?

https://youtu.be/y4gsQdhTK_s

Have fun !