Comparable Square Footage Adjustments.

[Debra]

Hello!

I'm wondering how the rest of you figure your comparable square footage adjustments...% of ? I know what I was taught while still in training but I'm wondering how everybody else does it and if the rest of you do it the same as we do? Thanks!

 

[MARKETVALUE]

What were you taught in training?

Of course the text book answer is that is depends on your market.....

MRM

 

[wyecoyote]

Marketvalue, your right on with that text book answer.

I grid my comparable sales first then sit back and look at them. This tells me what to adjust for what. Usually start with GLA and see if that makes any difference.

I do remember and old appraiser saying at a class that I was taking. He uses 30% of the cost new for the adjustments. I thought that was kinda odd what happens when the market says less?

Ryan

 

[airphoto]

The way I heard it was 1/3 of the selling value/square foot (on the theory that 1/3 of that was land value, and that half of the remainder (or another 1/3) was appropriate for a marginal contribution. Simplistic, but generally effective ..

However, if I'm fortunate enough to have bracketed GLA with my comps I'll usually iterate the adjustment values so as to minimize the grid value variation, after having done all the other adjustments ..

 

[Pamela Crowley (Florida)]

Just wait for Austin to find this one!

I do the GLA as the last adjustment and let the grid tell me what it should be. Sometimes/often - I'll have at least 6 comps on grid when I haven't done one in that area for a while.

The one thing that is for sure: IT DEPENDS - on your market, the subdivision, age, style, site, location, etc..... THERE IS NO 'GENERAL RULE OF THUMB' GLA ADJUSTMENT - anyone that tries to tell you there is is ........ uhm...... (trying to be nice here) not a very good appraiser. :roll:

 

[wyecoyote]

Wow,

Pamela your tongue hurt from bitting down hard on it?? :twisted:

Ryan

 

[Restrain]

O.K., I'm going to use the forbidden words "Multiple Regression Analysis". In a nutshell, that's what you do. Make your other adjustments first (garage differences, porches, pools, etc.,) and what's left over is the size adjustment. Then take your sales and compare them against each other. The difference in sales price divided by the square foot difference gives you your adjustment BY THAT COMPARISON. Do that by all the sales and you should get a reasonable estimate. If one is way out of kilter, take another look at your other adjustments.

Good luck.
Roger

 

[Richard Carlsen]

For non-waterfront houses or those located on medium to large acreage parcels, I generally find that 20 to 30% of the SF selling price works well in our market and makes the most sense. I usually do everything but the SF adjustment and then start with 20% and sit back and look.

For waterfront where site value can be 60-90% of the value, it is strictly a SF adjustment and that is typically 25-30% of the SF cost in the Cost Approach.

 

[Mike Garrett RAA]

Market perception of value. There is no rule of thumb. Would you use the same adjustment for a $75,000 property that you use for a $300,000 property?

I don't use such big words as Multiple Linear Regression but I do extract the data from the market through the use of "Pairs Analysis". Does it come out to be 1/3rd of cost new? Maybe, maybe not....extract the data and find out.

Thus sayth the old guy..who is feeling really old these days!