topic Re: Roof angles in Modeling

Roof angles

Arcadia — Tue, 23 May 2023 12:47:49 GMT

Something that has long frustrated me: why is there no option in the roof panel settings to use degrees/minutes/seconds for the angle. The only options are percent and decimal degrees even though I have degrees minutes seconds selected in my unit section of project preferences. Is there something I have missed?

Re: Roof angles

Anonymous — Thu, 01 Sep 2011 23:53:56 GMT

You use degrees, minutes and seconds for slopes? I've never heard of that before. What is the advantage?

Re: Roof angles

Arcadia — Fri, 02 Sep 2011 00:33:24 GMT

I don't always but I would like to be able to. Local building practise for traditional 'stick' pitched roofs in Western Australia refer to a range of roof pitches that are in degrees minutes seconds. Carpenters have a roof table book that provides them rafter plumb cuts etc based on these standard pitches. In most cases rounding up or down to the nearest degree or half a degree is accurate enough for the model but I will still prefer the option of using these settings. Of course I can convert the deg/min/sec to decimal but that is a nuisance.

Re: Roof angles

Barry Kelly — Fri, 02 Sep 2011 04:04:07 GMT

It has been a long standing issue.

http://archicad-talk.graphisoft.com/viewtopic.php?t=27185&postdays=0&postorder=asc&highlight=pitch&&start=0

I don't know why the working units don't control this.
It seems someone got it to work once but it seems to be almost impossible to reproduce.

Barry.

Re: Roof angles

Erika Epstein — Fri, 02 Sep 2011 13:30:12 GMT

Arcadia wrote:
Of course I can convert the deg/min/sec to decimal but that is a nuisance.

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Re: Roof angles

Steve Jepson — Thu, 08 Sep 2011 06:09:35 GMT

Arcadia wrote:
I don't always but I would like to be able to. Local building practise for traditional 'stick' pitched roofs in Western Australia refer to a range of roof pitches that are in degrees minutes seconds. Carpenters have a roof table book that provides them rafter plumb cuts etc based on these standard pitches. In most cases rounding up or down to the nearest degree or half a degree is accurate enough for the model but I will still prefer the option of using these settings. Of course I can convert the deg/min/sec to decimal but that is a nuisance.

I would be very curious to see what sort of framing square they use to measure a roof pitch like that. ( deg, min, sec ) and how it relates to side cuts for hip and valley rafters.

If they have to convert it from deg, min, sec, why was it specified that way in the first place ? No matter where you are in the world, plans aught to be made specifically for the guy who is building it. No bastard pitch with out a very good reason.

Re: Roof angles

Arcadia — Thu, 08 Sep 2011 06:25:19 GMT

Steve, I did say it was local practise so specifing a pitch like that IS designing for the guy who has to install it. The carpenters who install these traditional pitched roofs (as opposed to truss roofs which are becoming more common) just refer to a table which tells them the exact rise per metre and the length of the rafter plumb cuts so they don't have to measure any angles. Is that a good enough reason for you?

Here is the source of the tables:

http://smartcontractor.com.au/hancock.html

Re: Roof angles

Steve Jepson — Thu, 08 Sep 2011 08:29:25 GMT

Don't be silly. If you have to use a book to cut a roof your doing it wrong.

All of the information you need to cut a rafter is derived from the framing square.
The framing square works with ratios not angles so there are no angles to measure. Everything is based on the ratio of rise to run. ( Pitch ) Side cuts for hip and valley rafters, difference in length of jack rafters, brace measure, scale of 8's, 100th inch scale, essex board measure, etc... it's all derived from the framing square. A good one is stainless steel, thicker at the heel, drilled at the inside corner so you can tune it for square with a nail set.
Sadly, the use of the framing square is becoming a lost art.

Is there any equivalent to the Framing Square in Australia or just a carpenters square like we have here that you can use for plumb cuts and such but without the other information on it?

Is that why they need a book...because there is no such thing as a Framing Square in Australia? Is it not a common practice in Australia to give the angle of the roof in pitch ( a ratio ) so the carpenter will not need to measure any angles? I am not trying to be difficult, I am just ignorant and curious about it.

Re: Roof angles

Arcadia — Thu, 08 Sep 2011 08:52:34 GMT

I am sure there are a lot of things you don't understand about Australian building practices but no doubt their are things that I would find strange about the practices you have over there. Don't assume that because someone else does it differently to you that it is wrong.

Re: Roof angles

Steve Jepson — Thu, 08 Sep 2011 09:25:34 GMT

I am asking questions so I don't have to make assumptions.

We have books like that too. But they are for carpenters who don't know how to use a framing square. There is little or no information in them that can not be found on the framing square if you know how to use it.

So what I am interested to know is if the reason an architect in Australia uses deg, min, sec on his plans is because he is like most ignorant american architects and have no concept of how to use a framing square or is it is because Australian carpenters are like most American carpenters who don't know how to use a framing square either?

In other words is the art using the Framing Square something that has vanished from Australia like it is doing here, or was there never any such equivalent there anyway.

Do Australian carpenters typically work with a framing square and ratios or do they prefer to work with angles ?

It sounds to me like the reason for the books is because the carpenters would prefer to work with ratios and a framing square but the plans are not compatible when the architects use deg, min, sec for the roof angles.

Just like here, perhaps I would need to ask an old Australian carpenter rather than an architect about that.

Re: Roof angles

Arcadia — Thu, 08 Sep 2011 11:07:20 GMT

Yep maybe you should ask an Aussie Carpenter.

Re: Roof angles

Anonymous — Mon, 30 Jan 2012 07:56:30 GMT

Arcadia,
To using Deg Min Sec, you would probably find it easy to use an online coverter such as the one at the following link. It provides conversions between Deg Min Sec and Decimal degrees.
My understanding is that ACAD calculates angles in Dec degrees. If you want to enter the degrees to more than 2 decimals you may need to alter your settings.
http://www.satsig.net/degrees-minutes-seconds-calculator.htm

Steve,
Yes, in Australia conventiional roof framing is set out by pitch (rise over run) and the use of a Framing Square.
Convential roof framing is a rarity though with most framed roofs being delivered as a set of trussed on the back of a truck.

Re: Roof angles

Arcadia — Mon, 30 Jan 2012 08:20:21 GMT

Thanks Graham, I actually did find a similar convertor which I have used. Yes the conventional roofs are almost non-existent in the eastern states but still very widely used in South West WA (where I do a lot of jobs). This is slowly changing though and I expect trusses will replace everything eventually.

Re: Roof angles

Anonymous — Mon, 30 Jan 2012 09:43:58 GMT

OK, and I am guessing that few of our contributors - including me - would have a sense of what construction practices are like at Albany 500km south of the "most remote capital city in the world" (i.e. Perth, WA) - on the edge of the Southern Ocean, facing Antarctica. Abundant tall Kauri forests for timber, mines in the more remote northern Western Australia taking all the skilled trades.
All the best.

Re: Roof angles

Arcadia — Mon, 30 Jan 2012 09:58:30 GMT

Sounds like you know the area. I have done literally hundreds of projects in Albany. Cheers.