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Hi BCO have had a look at our drawings for the extension and have come back with a list of amendments.

 

I have sent this list over to the architect and he has pointed out the things he's going to rectify and the things we need a structural engineer for.

 

I'm not sure how much involvement we need form a structural engineer, we currently are using one for drainage issues and I have asked him to design a lintel for us and he has quoted me for 6 lintels. We only have 1 needing to be more than 3 meters, building control initially advised me that we don't need a structural engineer design for lintels less than 3 meter. Does this sound right?

 

I'm trying to understand what being asked by BCO here, these are from his list of amendments. DJ is the architect and his comments are at the bottom: 

 

 Approved Document A – Structure

Provide structural design and calculations for all aspects that fall outside the scope of ADA, to include, openings over 3m and return less than 665mm for the store room, floor joists, mid span noggins to flat roof and the foundation design due to drainage being deep to rear elevation.

2.    Existing beams will need to be uncovered to confirm adequacy, no application has been submitted for the opening into the existing conservatory.

3.    Confirmation required for the proposed lintel to be installed at first floor for the extension.

DJ Comment  - All should be provided by a suitably qualified Structural Engineer
 
 
 
Its the first part I cant understand, we don't have any opening above 3m except for the one that's already existing and is subject to verification/replacement.
 
When I ask BCO about things they seem unwilling, I was told today that "we cant design it for you". They may as well be talking in a different language some times. It seems they would be rather be dealing with a builder/agent, understandably.
 
I don't have the luxury of having this done for me, and we need the extension badly.
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8 minutes ago, ProDave said:

If the architect cannot understand what the BCO is saying, you have the wrong architect.

It's me that's puzzled, I would imagine the architect is up on things but I cant work exactly what I need an SE for as I cant afford to pay out for unnecessary work.

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My guess is the BCO was in a rush and just didn't have time to check if you actually had any lintels over 3m. That will be from his normal list of things to ask for. It's not uncommon for the most critical lintel to be designed by the SE and the same family of lintels be used for the other smaller windows (eg same depth and width just different length). But note its not always the longest lintel that is the most critical. I would ask the SE to provide calculations for the one that might need replacing and possibly recommend a family of lintels for the windows. Tell him BCO says he doesn't need calculation for lintels under 3m. The SE might decline and insist on doing load calculations for all of them because you are effectvely asking him to take on risk without doing sums he feels are needed. 

 

Not 100% sure what the "return less than 665mm for the store room" is but it sounds like it might be a pier/pillar or short length of wall perhaps between two windows or a window and a door. Theses are typically areas where the loads are concentrated. Eg it's got the ends of lintels or other beams resting on it. In some cases the load may be high in relation to the crush strength of lightweight blocks. The SE can do a calculation and tell you exusting blocks are ok or what density of blocks to use if its a new part of the build.

 

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21 minutes ago, Temp said:

My guess is the BCO was in a rush and just didn't have time to check if you actually had any lintels over 3m. That will be from his normal list of things to ask for. It's not uncommon for the most critical lintel to be designed by the SE and the same family of lintels be used for the other smaller windows (eg same depth and width just different length). But note its not always the longest lintel that is the most critical. I would ask the SE to provide calculations for the one that might need replacing and possibly recommend a family of lintels for the windows. Tell him BCO says he doesn't need calculation for lintels under 3m. The SE might decline and insist on doing load calculations for all of them because you are effectvely asking him to take on risk without doing sums he feels are needed. 

 

Not 100% sure what the "return less than 665mm for the store room" is but it sounds like it might be a pier/pillar or short length of wall perhaps between two windows or a window and a door. Theses are typically areas where the loads are concentrated. Eg it's got the ends of lintels or other beams resting on it. In some cases the load may be high in relation to the crush strength of lightweight blocks. The SE can do a calculation and tell you exusting blocks are ok or what density of blocks to use if its a new part of the build.

 

BCO always seems to have no time, I reckon your spot on there.

 

I'll talk to SE tomorrow, I'll first explore exposing the current lintel and hope it's adequate.

 

The SE has also added a "wind post" in, no one else has mentioned that?

 

Your probably right about the "return less than 665 for the store room" as it looks like there will be two lintels bearing on one wall there. I have put a blue circle around where i mean.2021-10-06.thumb.png.c60c8b6fef0d354d963f6fc57871fa1c.png

 

Thanks for the help!

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Now I've seen the drawing..

 

The left hand wall on your drawing above is quite long. Long walls need buttressing which is normally provided by interior walls. So its probably the bit of wall on the other side of the door to the point you marked that the BCO is interested in. Is that where the SE added a wind post? The resolution isn't good enough to make out. 

 

 This stuff is in Approved Document A around page 28 but takes some working out. 

 

Edit: Now I look again I see that probably is where he's put the wind post (marked RWP).

Edited by Temp
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2 hours ago, Paul Alan said:

no application has been submitted for the opening into the existing conservatory.

 

Not 100% sure what this is about but..

 

Conservatories come under different building regs to other rooms. In general they can have more glass and less insulation provided an exterior grade door is retained between the house and conservatory. In addition any heating has to be seperately controlled to the main house.

 

If someone has knocked through or removed the door in the past,  or if this is part of your current plans, you may need to demonstrate the resulting new/larger room meets the regs as a whole. Last time I looked there were several calculations you could do to prove this. You start with the easier sums and if they show you dont meet the regs there are more complicated calculations you can do that take into account insulation elsewhere in your house. 

 

So the BCO could be saying that no application has been made for this in the past or that he doesn't think you have submitted enough information with the current application or something else along these lines.

 

If you are knocking through into the conservatory as part of the extension and your Architect has been paid to do the Building Control Application drawings then he should do these calculations to insure compliance with Part L.

 

 

 

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I’m no expert and your Approved Documents are slightly different from our Technical Booklets but:

 

Approved Document A – Structure

Provide structural design and calculations for all aspects that fall outside the scope of ADA, to include, openings over 3m


Can’t see the dimension of the rear opening but if it’s over 3.0m it’s outside the scope of the approved document. Simply reduce the opening to 3.0m but make sure that the opening is less than 2/3 of the rear wall length measured from the centre of the cavity to the centre of the cavity. Your agent can do this.

 

and return less than 665mm for the store room

There is a wind post there. You won’t need a return pier.

Double check that the upstairs front and rear corner external piers are not less than 665mm.

Your agent can do this.

 

floor joists

Your agent should be able to size these for you.

Your approved document do have span tables - ours do.

 

mid span noggins to flat roof

Should only be required for floors not flat roofs but I could be mistaken. Just need to get your agent to specify timber struttting to the flat roof joists (and timber floor joists) if that’s what the BCO wants. A couple of rows at 1/3rd span should do.

Your agent can do this.

 

and the foundation design due to drainage being deep to rear elevation.

You might need to pile the foundations if the site is fill. If this refers to new drainage then fill the drainage trench with concrete from the top of the drainage pipe to the underside of the foundations. You may need an SE but I’d try the BCO with a note stating that the design of the foundations will be a contractor designed item with the design forwarded to BC once trial holes have been excavated on site. Worth a try. You should also see what your existing foundations are by asking the BC Department for records or excavating a trial hole.

 

2.    Existing beams will need to be uncovered to confirm adequacy, no application has been submitted for the opening into the existing conservatory.

 

Sounds like they may be referring to an opening that they never knew about, do not know what type of lintel was used and are concerned that the lintel will not support the additional flat roof loading. They may also ask you about fire protection to this lintel.

You will need a SE to look at this for you.

 

3.    Confirmation required for the proposed lintel to be installed at first floor for the extension.

Specify a new lintel across both openings.

Your agent can do this.

 

Most of the queries from the BCO can be answered by your agent. There are however a couple that an SE will need to look at.

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8 hours ago, Temp said:

 

Not 100% sure what this is about but..

 

Conservatories come under different building regs to other rooms. In general they can have more glass and less insulation provided an exterior grade door is retained between the house and conservatory. In addition any heating has to be seperately controlled to the main house.

 

If someone has knocked through or removed the door in the past,  or if this is part of your current plans, you may need to demonstrate the resulting new/larger room meets the regs as a whole. Last time I looked there were several calculations you could do to prove this. You start with the easier sums and if they show you dont meet the regs there are more complicated calculations you can do that take into account insulation elsewhere in your house. 

 

So the BCO could be saying that no application has been made for this in the past or that he doesn't think you have submitted enough information with the current application or something else along these lines.

 

If you are knocking through into the conservatory as part of the extension and your Architect has been paid to do the Building Control Application drawings then he should do these calculations to insure compliance with Part L.

 

 

 

There was a conservatory at the back of the house which we have since removed to accommodate the extension, BCO has noticed that there wasnt any records of plans done for it 20 years ago. He wants the lintel verified.

 

I have asked the SE and he's offered to design a replacement or verify the one that's there. 

 

I have a feeling it needs replacing, the opening is 2.8m and from the outside it looks like there is only 100mm standing either side. I need to remove some bricks to be sure.

 

We paid the architect to do some basic drawings, I am unsure of how much responsibility he has. 

 

 

Thanks

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11 hours ago, Paul Alan said:

Hi BCO have had a look at our drawings for the extension and have come back with a list of amendments.

 

I have sent this list over to the architect and he has pointed out the things he's going to rectify and the things we need a structural engineer for.

 

I'm not sure how much involvement we need form a structural engineer, we currently are using one for drainage issues and I have asked him to design a lintel for us and he has quoted me for 6 lintels. We only have 1 needing to be more than 3 meters, building control initially advised me that we don't need a structural engineer design for lintels less than 3 meter. Does this sound right?

 

I'm trying to understand what being asked by BCO here, these are from his list of amendments. DJ is the architect and his comments are at the bottom: 

 

 Approved Document A – Structure

Provide structural design and calculations for all aspects that fall outside the scope of ADA, to include, openings over 3m and return less than 665mm for the store room, floor joists, mid span noggins to flat roof and the foundation design due to drainage being deep to rear elevation.

2.    Existing beams will need to be uncovered to confirm adequacy, no application has been submitted for the opening into the existing conservatory.

3.    Confirmation required for the proposed lintel to be installed at first floor for the extension.

DJ Comment  - All should be provided by a suitably qualified Structural Engineer
 
 
 
Its the first part I cant understand, we don't have any opening above 3m except for the one that's already existing and is subject to verification/replacement.
 
When I ask BCO about things they seem unwilling, I was told today that "we cant design it for you". They may as well be talking in a different language some times. It seems they would be rather be dealing with a builder/agent, understandably.
 
I don't have the luxury of having this done for me, and we need the extension badly.

 

post up the drawing. 

 

How deep are your footings and who decided that ?

 

If the opening has a small pier for the lintel to sit on it reduces the span your allowed to use without an SE designing it. 

 

Should have saved the money and not bothered with architect and used an SE and your own drawings. As you have found out they are useless.

 

Just a tip, make sure your structural openings work brick this not only will save your bricky time but make it look a lot better without dog rough cuts. Architects are normally clueless about this and spec windows/doors such a 700, 800, 1500 etc which all don't work brick. Whatever they spec divide by 225 and then round up to the the closest whole number or half. eg 700 window is wither 675mm or 787mm. 

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8 hours ago, ETC said:

 

 

I’m no expert and your Approved Documents are slightly different from our Technical Booklets but:

 

Approved Document A – Structure

Provide structural design and calculations for all aspects that fall outside the scope of ADA, to include, openings over 3m


Can’t see the dimension of the rear opening but if it’s over 3.0m it’s outside the scope of the approved document. Simply reduce the opening to 3.0m but make sure that the opening is less than 2/3 of the rear wall length measured from the centre of the cavity to the centre of the cavity. Your agent can do this.

 

and return less than 665mm for the store room

There is a wind post there. You won’t need a return pier.

Double check that the upstairs front and rear corner external piers are not less than 665mm.

Your agent can do this.

 

floor joists

Your agent should be able to size these for you.

Your approved document do have span tables - ours do.

 

mid span noggins to flat roof

Should only be required for floors not flat roofs but I could be mistaken. Just need to get your agent to specify timber struttting to the flat roof joists (and timber floor joists) if that’s what the BCO wants. A couple of rows at 1/3rd span should do.

Your agent can do this.

 

and the foundation design due to drainage being deep to rear elevation.

You might need to pile the foundations if the site is fill. If this refers to new drainage then fill the drainage trench with concrete from the top of the drainage pipe to the underside of the foundations. You may need an SE but I’d try the BCO with a note stating that the design of the foundations will be a contractor designed item with the design forwarded to BC once trial holes have been excavated on site. Worth a try. You should also see what your existing foundations are by asking the BC Department for records or excavating a trial hole.

 

2.    Existing beams will need to be uncovered to confirm adequacy, no application has been submitted for the opening into the existing conservatory.

 

Sounds like they may be referring to an opening that they never knew about, do not know what type of lintel was used and are concerned that the lintel will not support the additional flat roof loading. They may also ask you about fire protection to this lintel.

You will need a SE to look at this for you.

 

3.    Confirmation required for the proposed lintel to be installed at first floor for the extension.

Specify a new lintel across both openings.

Your agent can do this.

 

Most of the queries from the BCO can be answered by your agent. There are however a couple that an SE will need to look at.

Thanks,

 

Were having the opening reduced to 2.4 so the lintel should only be 2.7m.

 

The foundations have been dug and there are some drainage issues, the soil pipe goes under the footings and under next doors conny. The SE is in talks with welsh water trying to convince them not to divert.

 

We have no agent! We dont have the money, I know it seems mad but me and my wife have no bedroom and its been this way for 8 years. It's an awkward situation but her divorce from her previous husband turned out to be way more costly than she initially though when we committed to this process, taking nearly 50% of our budget and leaving us in this predicament.

 

Welsh water are throwing extortionate figures around for a diversion and the whole thing is turning into a nightmare, I can see we didn't do our research properly.

We also had some bad advice etc but theres only one way out of this and the build will ultimately get done.

 

I feel like I'm really up poo creak without a paddle but we have 2 kids etc etc so I need to sort this out.

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2 minutes ago, Dave Jones said:

 

post up the drawing. 

 

How deep are your footings and who decided that ?

 

If the opening has a small pier for the lintel to sit on it reduces the span your allowed to use without an SE designing it. 

 

Should have saved the money and not bothered with architect and used an SE and your own drawings. As you have found out they are useless.

 

Just a tip, make sure your structural openings work brick this not only will save your bricky time but make it look a lot better without dog rough cuts. Architects are normally clueless about this and spec windows/doors such a 700, 800, 1500 etc which all don't work brick. Whatever they spec divide by 225 and then round up to the the closest whole number or half. eg 700 window is wither 675mm or 787mm. 

Thanks,

 

The BCO had us go 1m deep to match the existing footings of the house, its clay.

 

Hindsight is a wonderful thing!  I may not have even got myself in this mess if I had it.

 

 

72 Lon Glanfor - Building Regulations Drawings.pdf

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