Calculating square footage of houses

ilikecookies

Hello,

Is there a standard method to calculate the square footage of a house?

I ask as part of the househunting process I'm finding some quite big discrepancies between data points (ie. the total floor area reported on the SAP report and the published dimensions on Rightmove). Most sales particulars don't include dimensions for some areas (eg. if a hall or communal area has strange dimensions) so it's often difficult to tot the numbers up.

This got me wondering if there a particular way this should be done? For example, to get some perspective I went outside and measured the external dimensions of my house to calculate the square feet for the ground floor which I then times by 2 to get the total for both floors. I then took internal measurements of every room (using a laser measure so should be pretty accurate) and found the difference was quite big. For example about 2800 square metres when measured externally but 2200 when measuing the rooms internally.

I understand there will be loses due to the thickness of the external walls, internal walls etc. But it got me thinking about how this should be done - eg. do stairs count as floor space?

Any advice gratefully received!

Thanks

noh

For example about 2800 square metres when measured externally but 2200 when measuing the rooms internally.

That's a very big house!
Do you mean 2800 sq feet not metres?

I found the same as you when we purchased this house. There were three different figures produced. One from the estate agent one from the EPC and one from the building survey.
The only one I trust is the surveyors which is stated as being based on the external measurements. The EPC is a rough guess!

There appears to be a standard method for insurance purposes which is to measure the gross external floor area
https://abi.bcis.co.uk/measuring_your_house/measuring.aspx

3mph

It is going to depend upon what it is being used for.
External for building insurance since its the building being covered.
Internal where the tape is held out the window with the EA assistant holding onto the EA's feet, for sales purposes.
Rooms for fitting in furniture

But for comparison approximate overall internal dimensions. The EPC seems to do this.

Bearing in mind that layouts with huge or tiny halls will change the comparison.

ilikecookies

noh wrote: »

That's a very big house!
Do you mean 2800 sq feet not metres?

Sorry yes sq feet not sq metres! Heating and maintaining a 2800 sq ft property is a nightmare as it is!

Great will take a look at that guide!

From the flip side if we sell I want to ensure I don't under report the space but don't want to overstate it either for fear of misrepresentation etc!

ilikecookies

3mph wrote: »

It is going to depend upon what it is being used for.
External for building insurance since its the building being covered.
Internal where the tape is held out the window with the EA assistant holding onto the EA's feet, for sales purposes.
Rooms for fitting in furniture

But for comparison approximate overall internal dimensions. The EPC seems to do this.

Bearing in mind that layouts with huge or tiny halls will change the comparison.

That makes a lot of sense - especially the external measurements for insurance and internal more for sales purposes. Thanks!

googler

ilikecookies wrote: »

From the flip side if we sell I want to ensure I don't under report the space but don't want to overstate it either for fear of misrepresentation etc!

What do you think would happen if it were 'misrepresented'?

If you sell it privately, there's no legislation which covers the situation

If you sell with an EA, they'll measure it themselves and take responsibility for what they state in accordance with Consumer Protection Regulations.

lincroft1710

Gross Exernal Area = measurements round the outside of the property on each floor and added together.

Gross Internal Area = measurements round the inner part of the outside walls of the property on each floor and added together. You do not hang out of a window when measuring.

Net Internal Area = measurement of all rooms added together, some will include hallways, landings and staircases, others will not.

andrewf75

The first thing is do it in metres not feet. Trying to calculate anything in feet is just creating a nightmare for yourself.

paddycharlie

Does a garage usually get added to the square footage of a property?

eddddy

ilikecookies wrote: »

From the flip side if we sell I want to ensure I don't under report the space but don't want to overstate it either for fear of misrepresentation etc!

I think you might be over-thinking this.

Floor areas aren't generally included in house/flat sales details in the UK, and even if they were - the details would be 'subject to contract', so a claim for misrepresentation would almost certainly fail.

Some people do like to do total floor area comparisons when viewing multiple properties - but it's for their own personal use, so they can decide their own measurement rules.

I think people more often look at 'the bigger picture'....

e.g.
They might pay more for property with a bigger kitchen, but smaller 3rd bedroom - even though it's total floor area is smaller.

And/or they value a larger bedroom more than a larger bathroom (or vice versa).


(The only time floor area has come up as an important consideration for me is with very small studio flats - most mortgage lenders will not lend on flats under 30 sq m)

Surrey_EA

paddycharlie wrote: »

Does a garage usually get added to the square footage of a property?

It shouldn't do. Our floor planners always exclude garages and outbuildings, but it does vary.