Specified ridge height. Relative to what though?

[flanagaj]

The ridge height in the previously granted PP on our site and our revised planning application both have a ridge height of 6.4m, but not a single drawing states what the 6.4m height is taken from.  Is it taken as 6.4m from the road frontage, eg where your driveway starts from the highway?

[dpmiller]

I'd presume it was above FFL but hang on for confirmation...

[nod]

As above The ridge is measured from 

00 on your drawing (DPC)

[Russell griffiths]

And FFH should be defined on your TOPO survey. &nbsp
 

[flanagaj]

Here is the topo survey that was done, lots of elevation points, but I cannot see the datum point which the ridge height / FFL is based off.

[Ben1984]

It should have been specified on your planning drawings. Something like; Floor level 122.65. If your architect hasn't made any reference to the FFL on the plans it might be worth confirming with the planners (to avoid any potential problems in the future).

 

You could assume that FFL would be 150mm above ground level (if you are building on a flat site) but this is not always the case.

[flanagaj]

1 hour ago, Ben1984 said:

It should have been specified on your planning drawings. Something like; Floor level 122.65. If your architect hasn't made any reference to the FFL on the plans it might be worth confirming with the planners (to avoid any potential problems in the future).

Neither the revised planning application or the previously granted application specified any FFL measurement.   All very strange, as don't the planners want to know that?

[Mr Punter]

With PD applications, they take the max ridge height from the highest point of the ground around the building.  Is there a planning condition requiring further details on height?

[saveasteading]

It is seldom clear and seldom questioned.

I think I had an unhappy neighbour complain to the council once. 

We are talking 100mm or so.

It was very easy to show whatever was needed as long as it isn't a lot.

Reference to the origjnal ground makes most sense, and you could choose the highest point, esp as you of course usually build above that. But if you referred to floor level it would be OK.

The condition is not about 100mm but any large increase.

[ProDave]

All our planning drawings were done with heights referenced to a temporary bench mark which was a row of nails driven into a fence post on the highest corner of the site.  That is still there.

 

Surely a ridge height is only important when it does not want to exceed that of neighbours.  Nobody ever checked any of our heights.

[Russell griffiths]

All my planning drawings state FFH at 88.75 which when referenced to the TOPO shows exactly where it should be. 
 

you then take a fixed point from the TOPO like a manhole cover, for arguments sake, manhole at 87.75, so FFH  1m above that manhole, give or take a little bit, you generally bang a stake in well out the way and transfer all the crucial measurements to it, so you can then rip the site up and it doesn’t matter if the manhole gets disturbed. 

[Alan Ambrose]

I think this is a general loophole. In theory ridge height is from GL. Where’s GL? Unless it was specified on the PP drawings (not required by many LAs)  it’ s the highest point around the proposed building outline on your topo.  But the topo doesn’t cover every point on your plot, only some representative points. Once the topsoil has been stripped and the ground generally mangled by heavy machinery, where was it again?

[saveasteading]

3 hours ago, Alan Ambrose said:

where was it again?

It's so easy to specify.

I don't think planners are generally into such technicalities....eg that levels are easy to control.

Even when the height was  questioned during  planning apps,  numbers were not required. Show us a stick on site / show an artists impression.

[flanagaj]

So can I assume that as no FFL was specified in the planning application that I can choose the FFL (within reason)?  The topographic has a +/- 10cm, eg 122.90 and 123.00.  I personally would like to go with 123.00 as it means less excavation.

Given that nothing has been specified, what is the legal basis here? By going with 123.00 I do raise the house and remove the possibility of water running towards the house from the adjacent slope.

[saveasteading]

 

What is not clear?

 

Going back to your original question.

It is definitely about the height relative to the original levels at the building location, and not the drive, gate, highest part of the site.

 

If you want it as high as possible, choose the highest original ground level within the house area or the ffl.

 

if you add 100mm you will likely get away with it. Not a good idea to push your luck beyond that.

 

 

[flanagaj]

I did reach out to the planners today to try and ascertain what the ridge height is relative to, just so there is no ambiguity.  Their response was

 

"The planning permission is done against the original ground level.

 

As per the elevation plans approved we would expect that from ground level, the lower ground level is 0.48m below that and the the ridge of the dwelling is no more than 6.4m above the ground level."

 

When pressed what height is ground level, I received the below.

 

"Unfortunately this is not something as a planning officer that I can advise on, you would need to speak to a building surveyor who should be able to help in this regard."

 

So, it's still clear as mud.   I think I'll just take the highest topographic point where the dwelling will sit.

 

I am amazed that nobody requested the FFL ASL as part of the planning submission.

 

[Russell griffiths]

If it’s a detached property with a couple of metre gap between you and the neighbours, 100mm up or down wouldn’t even notice, so I don’t think they care that much. 
i would set it up as high as you dare, it will help with drainage runs and run off from the field behind, and your retaining wall will be shorter. 

[ETC]

From your FGL when the house is built. Sometimes combined with a maximum under build.

[flanagaj]

22 minutes ago, ETC said:

From your FGL when the house is built. Sometimes combined with a maximum under build.

Can you elaborate as I don't fully understand what you are saying.