I should have read the original title - I missed the extension bit and my
comments yesterday were really aimed at developments. For extensions MAPAC
developed a reasonable approach but I am not sure if they published it.
However we have used it in the Gas Handbook.
I have attached it below - so any constructive comments would be useful
before we get round to publishing.
Landfill and ground gas can be a potential hazard to health, as such if you
are planning to make structural alterations to a property that is within
250m of a known landfill site or within an area of suspected ground gas it
is likely that the Council will require you to install gas protection
measures.
Protection to extensions is generally required if:
. Existing building has protection measures
. Known problems with gas entering unprotected buildings in the area
. High risk landfill site nearby and gas migration is known to be occurring
from it close to the property considered.
In other situations where there is the potential for gas but the risk is low
and the existing property does not have gas protection measures then
protection to the extension may not be required.
If your property already has gas protection measures or the Council has put
a condition requiring gas protection measures on your planning approval for
your extension it is important that you install such measures. Such a
condition will only be placed on a planning approval if the Council believes
that the property and its occupants may be is at risk without these
protection measures.
If a building contains a certain specification of ground gas protection
measures then you should not construct an extension without protection or
with measures of a lower specification. Doing so may compromise the gas
protection measures to the whole property; therefore it is important that
every property extension constructed should contain gas protection measures
to at least the same specification of that in the existing building.
In cases where protection is required for an extension it should be possible
to design it without gas monitoring data and site investigation data. In
most situations it will comprise a membrane and possibly underfloor venting.
Steve Wilson, Technical Director
EPG Limited
Tel 07971 277869
www.epg-ltd.co.uk
-----( Disclaimer )-----
> >
Information contained in this e-mail is intended for the use of the
addressee only, and is confidential and may contain commercially sensitive
material. Any dissemination, distribution, copying or other use of this
communication, other than for which it is explicitly intended, without
the permission of the sender is strictly prohibited. If you have received
this
e-mail in error, please advise the sender immediately and delete it from
your system. Whilst all e-mails are screened for known viruses, the company
cannot accept responsibility for any which have been transmitted.
-----Original Message-----
From: Contaminated Land Management Discussion List
[mailto:[log in to unmask]] On Behalf Of Peter
Millis
Sent: 14 August 2007 23:06
To: [log in to unmask]
Subject: Re: Extensions within 250m of landfill.....
Surely there is a big difference between an extension to an existing
property and a new development? Your condition seems to be more applicable
to a new development. One of my jobs outside of research is working with a
friend on building extensions and conservatories on existing properties. In
all cases concrete floors covered over with vapour barrier membrane and
insulation panels are used, and in 100% of these extensions the integrity
of the extension is greater than that of the house onto which the extension
is being built! My personal opinion is that the conditions you are imposing
are unreasonable in terms of both timeframe and costs incurred by the owner
of the existing property. You would be better off just making it a
condition of building regs approval that a vapour barrier is in place right
from the start as the cost of this is only a few pounds and is
insignificant with respect to time when being incorporated within the build.
Regards
Pete Millis
Centre for Environmental Research
School of Life Sciences
University of Sussex
Falmer
Brighton BN1 9QJ
--On 14 August 2007 10:49 +0100 Mark Newman <[log in to unmask]>
wrote:
> Hello All,
>
> I asked a similar question a while back, but didn't get much of a
> response.
>
> I am getting a lot of planning applciations for extensions/conservatories
> within 250m of closed landfill sites. I have recently started using the
> condition:
>
> "Prior to commencement of development, a site investigation shall be
> carried out to include monitoring for methane gas. Monitoring should
> include sampling for methane, oxygen and carbon dioxide and should be
> carried out over a period of at least 2 months with a minimum of 8
> readings taken ? spike testing will not be accepted. The report,
> together with any recommendations for remedial works, must be submitted
> to and agreed in writing by the local planning authority. Such remedial
> works must be carried out prior to commencement of construction works.
> Prior to the discharge of this condition, details of any remedial
> measures used shall be submitted to the Local Planning Authority."
>
> Am i justified in asking for this, or would the condition below be
> suitable for these types of applcation:
>
> "A gas impermeable membrane should be incorporated within the structure.
> Any services entering/leaving the structure should be located above the
> gas impermeable membrane or adequate seals will have to be provided if
> the membrane has to be breached. Prior to the works commencing, details
> of the gas impermeable membrane should be submitted to and approved by
> the LPA."
>
>
> We have very little information regarding gas monitoring in the past, and
> what we do have is about 15 years old. So i cannot make a reliable
> judgement about whether or not the site is gassing. It is this
> uncertainty that makes me want to request gas monitoring each time....
>
> Any input on this would be very gratefully appreciated.
>
> Many thanks,
> Mark
>
> (Dover DC)
>
>
|
