# Calculating square footage of a vaulted ceiling



## AngieM (Apr 13, 2016)

I made a critical miscalculation estimating paint and area of this great room vaulted ceiling. I shorted myself almost $200 because of it because I charged by the square foot too. Ugh. 

Since I don't remember geometry from when I was in school, it took me a little while to figure this out. And since this is highly relevant to our field I thought I'd share. Although, I'm sure I'll get a bunch of replies like "duh Angie, everyone knows that"  

I know a laser measuring tape will do the same thing but here's the Trigonometry of the thing. This great room is 24 x 24 feet. 18 feet at the peak and 8 ft at the wall. I made the rookie mistake of taking 24 times 24 to get 576 square feet. That'd be great if I was painting the floor. The actual square footage of this ceiling is 768 square feet. Off by 192, or a full gallon of paint. 

To calculate the square feet of this vaulted ceiling I needed to use the Pythagorean Theorem. A^2 +B^2 =C^2. A and B are the right angle of the triangle. C is the Ceiling. A = 10 feet (18 at the peak, 8 ft at the wall) B = 12.5 ft (half the room). A squared is (10 times 10) 100. B squared is (12.5 times 12.5) 156.25. The sum is (100 + 156.25) 256.25. 

Now here's the exciting part! The square root of 256.25 is exactly 16. That ceiling I thought was 10 feet from the wall to the peak was actually 16! That's quite a difference. 

Take 16 multiplied by 2 (both sides) = 32 feet. Multiplied by the length of the room 24 and you get 768. NOT 576.

I left money on the table. That won't happen again. I deserve that extra $200 especially for the PITA factor. 

So there you have it. Telling you what you already know. Has anyone else made this mistake? 










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## kmp (Jan 30, 2011)

Well ,Angie you won't hear any of the everybody knows that from me since you lost me at A^.We have all lost money because of missing something on an estimate but we try to keep it to a minimum.Live and learn as they say.


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## AngieM (Apr 13, 2016)

A^2 is A squared. Can't find exponents on my keyboard.😊

Here's another mathematical equation I was trying to figure out. 

To mask that ceiling fan at the ceiling I contemplated strapping an extension ladder to an A frame ladder and having my helper stand and anchor the bottom while I climb to the top. 

So I'm thinking. I've seen Science of Stupid so I know all about center of gravity. As long as I keep the weight distributed on the right side of the pivot point I'll be good. He weighs 260, I weigh 120. I have 140 pounds on my side. But how far past the center can I go before that thing turns into a teeter todder? 

I couldn't figure it out so I rented a 14 ft A frame ladder. Better safe than sorry right. 

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## kmp (Jan 30, 2011)

What you can try is to take an extension ladder, with rubber end covers and put it on the vaulted ceiling and reach out to mask the fans.You might have your helper hold the ladder and you may have to do it from both sides.
I have climbed ladders the way you describe but is better with two people holding the ladder. Any wrong move can be exciting. Remember the size of the itch of your nose is directly proportionate to the size of what you are carrying. If your helpers nose itches think of what he is holding up.


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## PNW Painter (Sep 5, 2013)

I'd be happy if some of my estimating mistakes only cost me $200. Also, I think you made the right call renting a 14' frame ladder. 


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## ridesarize (Jun 19, 2012)

AngieM said:


> A^2 is A squared. Can't find exponents on my keyboard.
> 
> Here's another mathematical equation I was trying to figure out.
> 
> ...


Good news, you didn't miss out in as much as calculated since there is that flat spot up there which actually minimizes that vaulted sq footage, but not by much. Doing the long math though, I guess it's very little difference, so little that it's not worth showing my work.. :smile:

Oh half the room = 12 ft, not 12.5 too...
I came up with 768 sq ft as well, guestimating flat peak at 3 feet wide...
(10×10) + (10.5×10.5) = 210.25. sq rt of 210.25 = 14.5
(14.5 × 24) ×2 = 696
Plus flat peak - 3ft×24 +696 = 768 yup sounds about right.....


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## Eagle Cap Painter (Nov 14, 2016)

Measuring the flat peak (P) is the trickiest part. Don't forget your order of operations!

H-W=B
(F-P)/2=A
√(A²+B²)=C
(P+2C)*length of room=ceiling square footage


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## goga (Aug 6, 2015)

It is kind of cute to read people are quoting these kind of ceilings by SF and what is more amusing, trying to figure out those SF by a higher end geometry


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## PRC (Aug 28, 2014)

In 20 years I have never bid a repaint by sqft. We break them down by task or unit prices. I use footage for prints and that's about it.


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## AngieM (Apr 13, 2016)

PRC said:


> In 20 years I have never bid a repaint by sqft. We break them down by task or unit prices. I use footage for prints and that's about it.


I do the same but then I divide it out be square foot. 

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## Eagle Cap Painter (Nov 14, 2016)

goga said:


> It is kind of cute to read people are quoting these kind of ceilings by SF and what is more amusing, trying to figure out those SF by a higher end geometry


I'm baffled that anyone in a construction trade would think that a middle school understanding of mathematics is good enough. Take a remedial course from Khan Academy or something because you're leaving money on the table somewhere if high school mathematics intimidate you.


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## futtyos (Aug 11, 2013)

*Sq ft vs eyeball vs ?*



AngieM said:


> I do the same but then I divide it out be square foot.
> 
> Sent from my XT1635-01 using Tapatalk


AngieM, I like to figure out the sq ft myself on estimates, even if my partner (on large jobs) does not. It helps me figure out how much paint will be needed.

I can see how keeping track of sq ft could help in estimating average type jobs to get an idea of how fast one can roll, say, a 24 x 12 foot ceiling, as Gymshu mentions he put a new worker on in post #8 of the recent thread "Too Meticulous Worker." When it took the new guy 8 hours to get one coat on this ceiling, that was his last day.

The vaulted ceiling you show a photo of is not your average ceiling. If you misjudged the sq footage, it might only be 1/2 to 3/4 of a gallon extra paint per coat. I imagine that ceiling paint would be the cheapest of any of the paint you got for this job.

The vaulted ceiling, however, is not a regular 8" ceiling where one can drag around a 6" ladder to cut in, then roll with an average length extension pole. You had to rent a 14" step ladder which I am sure was lots of fun to move around the room.

PRC said "In 20 years I have never bid a repaint by sqft. We break them down by task or unit prices. I use footage for prints and that's about it."

You replied: "I do the same but then I divide it out be square foot."

Can you elaborate a bit more on how you bid this ceiling? I'm not trying to be critical, I am curious for my own sake when I get the next vaulted ceiling to bid on. I need all the help I can get figuring out jobs. If I told about some of my bids I fear that the moderators would move me over to the DIY Forum!

futtyos


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## loaded brush (Dec 27, 2007)

Can't help out on your math but can say for myself, always bidding by the hour rather than sq. ft. Ive never shorted myself. If it's a specialty situation like a vaulted ceiling, I double my usual hourly rate. Never failed me yet.


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## AngieM (Apr 13, 2016)

@futtyos. I should have clarified. I like to keep track of my production rates and gallons used in each job and then divide it by the square foot to see how I did. 

After spraying so many ceilings I know my spread rate for chb flat paint (popcorn ceiling) for 2 coats is 150 sq ft a gallon. 

I use ****on of masking. Add that. My slow helper. What I want to make. Plus overhead (my van needs ball joints) . Plus profit. Divide it all out by sq ft. And I always come out around 80 cents a sq ft for ceilings. 

So you see how I shot myself on this ceiling. I still made money and learned lots of great lessons so it was profitable. 

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## futtyos (Aug 11, 2013)

AngieM said:


> @futtyos. I should have clarified. I like to keep track of my production rates and gallons used in each job and then divide it by the square foot to see how I did.
> 
> After spraying so many ceilings I know my spread rate for chb flat paint (popcorn ceiling) for 2 coats is 150 sq ft a gallon.
> 
> ...


For some reason I cannot make emoticons, so thumbs up!  < except for smiley face.


futtyos


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## goga (Aug 6, 2015)

futtyos said:


> AngieM, I like to figure out the sq ft myself on estimates, even if my partner (on large jobs) does not. It helps me figure out how much paint will be needed.


It is interesting and kind of confusing, that ppl were involved in the trade for so long and have to pull out calculator to figure out the sq and paint quantity when looking at the site. All it takes is just a glance to know exactly how much it takes to cover the whatever you are looking at if there were so many sites which have being covered by previous performance. Professional.. meaning, it is a profession performed daily.

PS: nothing personal, just an observation.


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## goga (Aug 6, 2015)

Eagle Cap Painter said:


> I'm baffled that anyone in a construction trade would think that a middle school understanding of mathematics is good enough. Take a remedial course from Khan Academy or something because you're leaving money on the table somewhere if high school mathematics intimidate you.


For each his own, can not compare everyone to everyone, that's why life is cute, different each time you meet someone)


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## MurphysPaint (Nov 23, 2015)

Eyeballs or tape measures? I guess it depends on how accurate you want to be and how much information you'd like to have for future reference. For me it's square foot pricing to start, then plus or minus man hours based on exceptions. In my mind, a job that is 3% bigger should cost 3% more, and I'll take my laser measure over a guesstimate any day of the week.

Thanks for sharing, Angie 

Murph


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## goga (Aug 6, 2015)

MurphysPaint said:


> Eyeballs or tape measures? I guess it depends on how accurate you want to be and how much information you'd like to have for future reference. For me it's square foot pricing to start, then plus or minus man hours based on exceptions. In my mind, a job that is 3% bigger should cost 3% more, and I'll take my laser measure over a guesstimate any day of the week.
> 
> Thanks for sharing, Angie
> 
> Murph


Let Almighty bless America and the ones who make it look good))

3%? :biggrin:

There is a life to leave))


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## MurphysPaint (Nov 23, 2015)

goga said:


> Let Almighty bless America and the ones who make it look good))
> 
> 3%? :biggrin:
> 
> There is a life to leave))




3% (as an example) on annual gross sales of $100,000 is $3,000 (thanks, math). If operating costs are 50% (for example), then that $3,000 is actually 6% of your profit of $50,000 (more or less). This might concern someone who considers themselves a "business owner", more than someone who considers themselves (for example) "just a painter". Everyone need not burden themselves with such things. Different strokes.


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## goga (Aug 6, 2015)

Me was saying.. the job that is 3% bigger in my mind has at least 5% increase in price, not 3. That all I've meant.


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## Eagle Cap Painter (Nov 14, 2016)

Small things add up over time. An extra couple thousand dollars a year is huge for some of us.


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## ridesarize (Jun 19, 2012)

I know, that's at least 3 Festool sanders _and a vacuum plus attachment's worth.

_


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## AngieM (Apr 13, 2016)

All I have to say is I'm glad to be alive after this job. After masking a ceiling fan on stacked bakers scaffolding with jerry rigged pins to hold it together, I have a new appreciation for life. 

It's obviously been too long since I've done this. Kind of like giving birth. You forget the pain until you have to do it again. I'm sure you guys can relate with that 😉. 



















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## AngieM (Apr 13, 2016)

I had to rent another set of that scaffolding to stack on mine. When I returned it I told the guy, "next time when someone says they're renting this to stack maybe you should suggest the outrigs. Just a suggestion."

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## MurphysPaint (Nov 23, 2015)

Murph


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## Gwarel (May 8, 2012)

AngieM said:


> I had to rent another set of that scaffolding to stack on mine. When I returned it I told the guy, "next time when someone says they're renting this to stack maybe you should suggest the outrigs. Just a suggestion."
> 
> Sent from my XT1635-01 using Tapatalk


The outriggers make a huge difference in stability for sure. I carry 1/2' bolts for extra pins. I always put bolts in the holes under the spring pins that hold the platform, you can never be too safe.


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## Woodco (Nov 19, 2016)

How long do you think it will be before the homeowners want the fans painted a brighter white?


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## Eagle Cap Painter (Nov 14, 2016)

AngieM said:


> I had to rent another set of that scaffolding to stack on mine. When I returned it I told the guy, "next time when someone says they're renting this to stack maybe you should suggest the outrigs. Just a suggestion."
> 
> Sent from my XT1635-01 using Tapatalk


Doesn't OSHA call for outriggers and rails if your feet are >6' from the floor?


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## Jmayspaint (Mar 26, 2013)

Eagle Cap Painter said:


> Doesn't OSHA call for outriggers and rails if your feet are >6' from the floor?




Idk, I thought the rule was baker scaffolds had to have the outriggers if you went to three bucks. Not sure on that though, probably local variables too. 

The outriggers do make a big difference in stability, but they're cumbersome. 


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## ridesarize (Jun 19, 2012)

Absolutely outriggers are needed. I have the 6' and 4' perry scaffold just like what you used and I would have second thoughts getting on that fully raised on carpet and drops.. 

No offense intended but I would have just cut the walls in from a 16' extension ladder.
I understand after getting the scaffold set up it seems you might as well use it instead of pushing it aside and bringing in a 16.


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## Eagle Cap Painter (Nov 14, 2016)

I'd heard but can't confirm this was reduced to 6', but it looks like you're supposed to wear a harness and use the rails when over 10' on Baker? Am I reading that correctly, or is Baker a "supported scaffold" that requires either/or?

https://www.osha.gov/Publications/osha3150.pdf
OSHA’s scaffolding standard has several key
provisions:
• Fall protection or fall arrest systems—Each employee
more than 10 feet above a lower level shall
be protected from falls by guardrails or a fall arrest
system, except those on single-point and two-point
adjustable suspension scaffolds. Each employee on
a single-point and two-point adjustable suspended
scaffold shall be protected by both a personal fall
arrest system and a guardrail. 1926.451(g)(1)

Single-point and two-point suspension scaffolds: Both a personal fall arrest system and a guardrail system.


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## Paradigmzz (May 5, 2010)

Eagle Cap Painter said:


> I'd heard but can't confirm this was reduced to 6', but it looks like you're supposed to wear a harness and use the rails when over 10' on Baker? Am I reading that correctly, or is Baker a "supported scaffold" that requires either/or?
> 
> https://www.osha.gov/Publications/osha3150.pdf
> OSHA’s scaffolding standard has several key
> ...


With handrail no fall protection needed. Without handrail your getting a ticket if caught by Osha if 2 sections tall or over.


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## AngieM (Apr 13, 2016)

ridesarize said:


> Absolutely outriggers are needed. I have the 6' and 4' perry scaffold just like what you used and I would have second thoughts getting on that fully raised on carpet and drops..
> 
> No offense intended but I would have just cut the walls in from a 16' extension ladder.
> I understand after getting the scaffold set up it seems you might as well use it instead of pushing it aside and bringing in a 16.


I did cut in the other side with that werner ladder extended to 17 feet. Because it was already there, just thought I'd try it. No offense taken 😊

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## PACman (Oct 24, 2014)

I read this thread because i couldn't for the life of me figure out why it was going on so long. Then i read triggernomotree and now i know.


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## ridesarize (Jun 19, 2012)

AngieM said:


> I did cut in the other side with that werner ladder extended to 17 feet. Because it was already there, just thought I'd try it. No offense taken 😊
> 
> Sent from my XT1635-01 using Tapatalk


Thanks, and sorry for me even saying anything about the 16. No need for me even to criticize, don't know why I did. 

The room looks nice.


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## futtyos (Aug 11, 2013)

*Equipment*



AngieM said:


> All I have to say is I'm glad to be alive after this job. After masking a ceiling fan on stacked bakers scaffolding with jerry rigged pins to hold it together, I have a new appreciation for life.
> 
> It's obviously been too long since I've done this. Kind of like giving birth. You forget the pain until you have to do it again. I'm sure you guys can relate with that 😉.
> 
> ...


Nice scaffolding there.

futtyos


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## Gwarel (May 8, 2012)

AngieM said:


> I did cut in the other side with that werner ladder extended to 17 feet. Because it was already there, just thought I'd try it. No offense taken 😊
> 
> Sent from my XT1635-01 using Tapatalk


Whenever I have a platform like that in place I cut it in twice and roll a band with a 9". It makes it much easier to roll back in from the floor.


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## Gough (Nov 24, 2010)

Eagle Cap Painter said:


> I'd heard but can't confirm this was reduced to 6', but it looks like you're supposed to wear a harness and use the rails when over 10' on Baker? Am I reading that correctly, or is Baker a "supported scaffold" that requires either/or?
> 
> https://www.osha.gov/Publications/osha3150.pdf
> OSHA’s scaffolding standard has several key
> ...


These are bosuns' chairs and swing stages....


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## Gough (Nov 24, 2010)

AngieM said:


> All I have to say is I'm glad to be alive after this job. After masking a ceiling fan on stacked bakers scaffolding with jerry rigged pins to hold it together, I have a new appreciation for life.
> 
> It's obviously been too long since I've done this. Kind of like giving birth. You forget the pain until you have to do it again. I'm sure you guys can relate with that 😉.
> 
> ...


Going back to the original post, that first photo is a perfect example of why focusing on strictly square-foot pricing can be problematic. Anything beyond 9-foot walls with flat ceilings and that approach breaks down.


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## loaded brush (Dec 27, 2007)

ridesarize said:


> Thanks, and sorry for me even saying anything about the 16. No need for me even to criticize, don't know why I did.
> 
> The room looks nice.


I did not feel you were criticizing. I also wondered why the room wasn't done with possibly a 12 foot step ladder to cut the ceiling fans and a 16 to get around the perimeter. Seems like scaffolding for a room that size is a bit much. I understand if you don't run into those types of rooms too often one may not be adversed as to possibly easier set ups but that all comes with time when you do enough of them. Seems like I personally get those type of rooms with those ceilings lease twice a month and I have never used scaffolding to cut in ,plus I never spray, always roll those ceilings from the floor.


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## Eagle Cap Painter (Nov 14, 2016)

Gough said:


> These are bosuns' chairs and swing stages....


Never did get to use a bosun's chair, but I did have to paint antennae on the yardarms while in drydock. Talk about a real butt-clencher.


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## AngieM (Apr 13, 2016)

I just want to thank everyone from this forum and the forum itself for being such an amazing resource. It's helped me beyond measure in tackling these challenging jobs. Whenever I run into a problem the first place I search is google... Because Painttalk search is terrible. But I put "painttalk" with my keywords and most always find my answer. 

The second place I go is the Idaho Painter. Because I have thing for painters with big biceps in small shirts. That's the ONLY reason 😉

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## Zoomer (Dec 17, 2011)

My two cents worth. In all the years of my grandfather painting, my father painting and I painting as well we have never had somebody question if we over calculated for an additional gallon of paint or two. That being said we have also rarely had anybody question when we have given them a fair number for painting a ceiling such as this. I always calculate on the high side for ceilings such as this. On the rare occasion when somebody does question fare estimate we have given them we tell them well you could do it yourself or what do you think it would take in order to do this ceiling? With this question that we occasionally ask then every single time the customer will have us to the ceiling. Of course manners and stating it in a mannerly fashion work much better than coming off abrasively. Your formula is correct for the most part but in the big picture what does it matter spending all that time trying to calculate the amount of paint and trying to calculate pricing.
Working alone I always calculate higher than if I have a crew with me. This is just a guesstimate but I would say at the very most you might need 5 gallons of paint for two coats on the ceiling based on your picture. Variables would include if the ceiling is new, if the ceiling is textured heavily, if the ceiling is going with a dramatic color change, but if the ceiling is going with a crisper white then what is existing from the picture I would venture to say 5 gallons is more than enough to brush and roll that two coats or for that matter to spray painted east to west then north to south for uniform coverage. My grandfather and father stated to me many years ago that so much time is lost on trying to figure out exactly the square footage for every area to be painted. People will more likely rely on your skill level and your craftsmanship rather than calculating exact square footage.


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## Danahy (Dec 11, 2008)

Hourly worked great when I first started out, nowadays my hourly rate makes people shoot coffee out their nose. i charge by the task, and the task is figured out by the square foot and a spread sheet. (2 minutes and a laser measure - done)

Ceilings are x amount per sq' (surface type and footage gives material amount)
- Add on additional x amount for each linear foot of cutting around the perimeter (handles not all rooms being square, and scales well for stupid shaped rooms)
- add on x amount for each light, vent, fan that I have to cut around
- add on 10% for each foot higher than standard 8'
- add on a % if there is junk in the room I have to work around
- on a vaulted ceiling I charge as if the whole ceiling is the height of the peak (compensates having to use 2-3 different ladders)

I don't trust myself to figure this out on the fly, hence the little spreadsheet.

In the two minutes I'm there, I look for Length, Width, peak height, surface type, count lights/fans, junk/furniture present yes or no.. gone.


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## Eagle Cap Painter (Nov 14, 2016)

Getting ready to do the ceiling, and beams, and chimney on this A-frame; I opted to learn from Angie and set up scaffolding that keeps my shorts clean. Have to throw a 6' step on top to mask the fan still, but we had to rent it anyway and the setup time was maybe 10 minutes more than 2-level Baker would've taken and OSHA's been all over paint crews this month, so it's nice to be compliant.


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## jprefect (Mar 4, 2015)

AngieM said:


> A^2 is A squared. Can't find exponents on my keyboard.😊
> 
> Here's another mathematical equation I was trying to figure out.
> 
> ...



When you can't get it with a Little Giant, it's time to spring for some staging! A good set of stackable interior staging has been super helpful. I bought it for a job with a big ceiling like that, and especially if you have to do any work on tape joints up there, but even just for masking and coating. I got mine for $600-700ish new, for two x 6 foot sections, with outriggers and a safety rail. It puts your feet 12' in the air, so reaching 18-20' is not hard at all. 

Put that in your equation!

Also, to the idea of unit pricing, I have used it more and more. These days I spend a lot of time staring into a spreadsheet. I really like it though. I'm spending about half my time these days in the office, estimating jobs (not just paint jobs, but restorations, and shop builds too!) and I'm building sweet excel templates to do a lot of the work for me. You could use pythagreans theorum, or you could shoot the hypotenuse with your laser measure too. 

Keep up the good work Angie.


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## AngieM (Apr 13, 2016)

Eagle Cap Painter said:


> Getting ready to do the ceiling, and beams, and chimney on this A-frame; I opted to learn from Angie and set up scaffolding that keeps my shorts clean. Have to throw a 6' step on top to mask the fan still, but we had to rent it anyway and the setup time was maybe 10 minutes more than 2-level Baker would've taken and OSHA's been all over paint crews this month, so it's nice to be compliant.


See!? I knew my mistake would help someone do it right from the beginning. Thanks to this forum, I've avoided a lot of mistakes by learning from someone else's mishaps. I just wanted to pay it forward 😉

Sadly, mistakes and failure are the best teachers. Most of my education came from what NOT to do. 

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