soakaway + building regs query

slippie2

We are undertaking a renovation under the 2014 regs with a generic planning condition that all stormwater go to soakaways.

Firstly, in part H of the building regulations 2010 I read '1.5.8.2 Soakways for areas less than 100 m2 are generally formed from square or circular pits, filled with rubble or lined with dry-jointed masonry or perforated ring units. Soakaways serving larger areas are generally lined pits or trench type soakaways. For soakaways serving larger areas reference should be made to BRE Digest 365 Soakaway design.'.

We have less than 100m2 of impermeable site area per soakaway. Is a BRE digest 365 test and design required?

Secondly, who can and should be inspecting and certifying the soakaway (esp. if no BRE digest 365 design was done)? architect (assigned certifier), structural engineer (ancillary certifier), builder?

I realize that the structural engineer would be the obvious choice but he has not been helpful to date and based on past performance will probably look for extra money if we ask him. So, we would like to avoid involving him if at all possible.

Thanks for your help,

Slip

Gumbo

slippie2 wrote: »

We are undertaking a renovation under the 2014 regs with a generic planning condition that all stormwater go to soakaways.

Firstly, in part H of the building regulations 2010 I read '1.5.8.2 Soakways for areas less than 100 m2 are generally formed from square or circular pits, filled with rubble or lined with dry-jointed masonry or perforated ring units. Soakaways serving larger areas are generally lined pits or trench type soakaways. For soakaways serving larger areas reference should be made to BRE Digest 365 Soakaway design.'.

We have less than 100m2 of impermeable site area per soakaway. Is a BRE digest 365 test and design required?

Secondly, who can and should be inspecting and certifying the soakaway (esp. if no BRE digest 365 design was done)? architect (assigned certifier), structural engineer (ancillary certifier), builder?

I realize that the structural engineer would be the obvious choice but he has not been helpful to date and based on past performance will probably look for extra money if we ask him. So, we would like to avoid involving him if at all possible.

Thanks for your help,

Slip

I know that if our Building Control Inspectors where to question the soakpit, they could take the word of the Engineer.
ie. I would not want to see an architect explain to me the outflow figures of a soakpit, i would want them on Engineers headed paper/email. I would always look for BRE 365 if possible, it future proofs it imo even if its technically not required.

slippie2

kceire wrote: »

I know that if our Building Control Inspectors where to question the soakpit, they could take the word of the Engineer.
ie. I would not want to see an architect explain to me the outflow figures of a soakpit, i would want them on Engineers headed paper/email. I would always look for BRE 365 if possible, it future proofs it imo even if its technically not required.

thanks for getting back to me.

i understand that involving the engineer and doing a bre 365 would be best.

what i don't really understand is the extent of the inspection and certification required from the engineer under the new building regs. my guess was that this would only extend to the elements designed by him (just the structural elements of the house in our case).

so, if we agreed with the builder and arch to build a small wall or put a simple soakaway at a location and these adhere to the regs, can they sign off on it?

thanks again,

slip

Gumbo

slippie2 wrote: »

thanks for getting back to me.

i understand that involving the engineer and doing a bre 365 would be best.

what i don't really understand is the extent of the inspection and certification required from the engineer under the new building regs. my guess was that this would only extend to the elements designed by him (just the structural elements of the house in our case).

so, if we agreed with the builder and arch to build a small wall or put a simple soakaway at a location and these adhere to the regs, can they sign off on it?

thanks again,

slip

They should issue an Achillary Certificate to your Assigned Certifier if the AC is not designing it himself. The AC may decide not to accept that though. You must do what the AC wants here tbh.

Drift

Just to add that there can be as many ancillary certifiers as needed so there would be nothing to stop you getting a different engineer to design the soakaways (albeit a more expensive option I'd imagine).

Strolling Bones

slippie2 wrote: »

i understand that involving the engineer and doing a bre 365 would be best.

Not trying to be difficult or confrontational but the new building control regulations do slant heavily towards to owner as well as designers and certifiers. There is a legal onus on you to seek appropriate persons for all aspects of the works.

I am only saying that IF you were to take a fingers crossed / hope for the best approach and it failed - the legal liability could be determined to be yours alone.

slippie2

Strolling Bones wrote: »

Not trying to be difficult or confrontational but the new building control regulations do slant heavily towards to owner as well as designers and certifiers. There is a legal onus on you to seek appropriate persons for all aspects of the works.

I am only saying that IF you were to take a fingers crossed / hope for the best approach and it failed - the legal liability could be determined to be yours alone.

Thanks for the advice.

We are just trying to bypass the engineer (due to unnecesary problems and expense he has already created) where we think we can do without him and are willing to accept full legal responsibility for those decisions.

Slip

Gumbo

slippie2 wrote: »

Thanks for the advice.

We are just trying to bypass the engineer (due to unnecesary problems and expense he has already created) where we think we can do without him and are willing to accept full legal responsibility for those decisions.

Slip

But you cannot act as Assigned Certifier. You need to appoint a new AC in that case.

slippie2

kceire wrote: »

But you cannot act as Assigned Certifier. You need to appoint a new AC in that case.

Our architect is our AC. Could the AC certify the builder to design a small soakaway?

BryanF

Not unless the builder is competent to DESIGN the system. this is your engineers job.

slippie2

BryanF wrote: »

Not unless the builder is competent to DESIGN the system. this is your engineers job.

Thanks Bryan,

Is it entirely up to the AC to decide if someone is competent to design a soakaway or land drain/french drain/garden wall/pier etc. and are the criteria for competency defined in the building regs or elsewhere?

Also, when sizing a soakpit, can and should a rainwater harvesting tank be incorporated into the calculations or should it be ignored?

sydthebeat

slippie2 wrote: »

Thanks Bryan,

1. Is it entirely up to the AC to decide if someone is competent to design a soakaway or land drain/french drain/garden wall/pier etc. and are the criteria for competency defined in the building regs or elsewhere?

2. Also, when sizing a soakpit, can and should a rainwater harvesting tank be incorporated into the calculations or should it be ignored?

YES

as the assigned certifier has to basically take responsibility for all trades and services on site, its up to them to determine (and accept) whether certain people are competent.

2. yes, rainwater harvesting would be included as an attenuation area

slippie2

sydthebeat wrote: »

as the assigned certifier has to basically take responsibility for all trades and services on site, its up to them to determine (and accept) whether certain people are competent.

Thanks Syd.

I would imagine an AC with absolute control over all contractor selection could lead to disputes with the owner.

What happens where the AC and owner disagree over contractor competency?

Is the only option an expensive and messy parting of the ways or would there be any option for some sort of 'letter of comfort' from the owner stating that they are fully aware of the ACs misgivings and accepting liability for any problems which this contractor selection causes.

Slip

Strolling Bones

slippie2 wrote: »

What happens where the AC and owner disagree over contractor competency?

If you change your AC you must inform the LA within 14 days. That change will be avaialble for future purchasers to note.

An AC would want his head examined if s/he accepted a letter of comfort as you describe it - it would have no legal affect.

slippie2

I guess the part I am unclear about is whether the criteria for competency are defined and standardized in the building regs or elsewhere.

If not, then I assume individual ACs will require different standards of competency?

sydthebeat

slippie2 wrote: »

I guess the part I am unclear about is whether the criteria for competency are defined and standardized in the building regs or elsewhere.

If not, then I assume individual ACs will require different standards of competency?

no, the criteria is not listed or standardised anywhere.

“Competent Person”: a person is deemed to be a competent person where, having
regard to the task he or she is required to perform and taking account of
the size and/or complexity of the building or works, the person possesses
sufficient training, experience and knowledge appropriate to the nature of
the work to be undertaken;

from here

its the owners responsibility to appoint the 'competent person'.... however the AC has to be satisfied this person is competent.

Gumbo

Will you get your plumber to design the lighting layout. No.
Will you get your sparks to design the plumbing. No.
Soak pots have an environmental effect, could lead to flooding etc so best bet is to have it spdesigned by an engineer.