Structural assessment of roofs for PV - Building control approval

[rt1200]

Please see attached pdf guidance note relating to the structural assessment of roofs prior to fitting PV arrays and the requirement for Building Control Appproval, if you are not registered as a competent person/body in the CPS scheme. MSC is not CPS. I hope you will find this useful as it is fact and not just someones opinion!

In summary many if not most PV arrays will require a structural assessment of the existing roof, or the proposed new roof to ascertain that if it can safely take the loadings. Many local building control officers are struggling to come to terms with what this means and its implications. They are not competent themselves and will/should ask for a structural engineers report. Some appear to be confused and talk only of the electrical installation. Nevertheless, as you will see in the attachment, it does relate to structural stability. Under the CPS scheme a competent person would virtually have to be a structural engineer to properly assess.

The bottom line is that a structural engineer is required whether you are CPS or apply for Building control approval via a building notice. Incidentally, the cost of the LA approval is related to the work itself. NOT ALL the work - just that related to strengthening the roof, so in most circumstances it shouldnt be hundreds of pounds. View attachment 6798View attachment 6798

 

[TedM]

I note that the document was written on 6th May 2011. I wonder where it's been hiding for the past 2.5 months.

It also seems less than totally definitive - still allowing an assessment to be made as to whether the 15% limit is exceeded or not. 15% itself is only a rule of thumb, as are all the 'guidelines' in the Building Regs.

And leaving some doubt as to which CPS does cover Part A or not seems inadequate. Part P schemes are a CPS without any doubt even if the double-talk around MCS accreditation says that they are not. Are there any PV installers who are not also in a Part P scheme?

The part that it does seem to clarify is that a Part A application is only required when strengthening work is carried out to a roof and that work is based on an engineers report that is only required if the 15% limit is exceeded - and that any BR fee is based only on the cost of the strengthening work and not the total job cost. That, at least, is useful.

 

[BruceB]

I note that the document was written on 6th May 2011. I wonder where it's been hiding for the past 2.5 months.

It has been in the hands of all the Building Control Bodies and the registration bodies since then and is what was informing the views of the BCBs. I was slipped a copy in early Jun, but my registration body did not want to be seen to be publically releasing it as it was not theirs to release. It does irritate me when quasi public bodies that effectively we as the public have funded do not place stuff like this in the public domain.

But at least some BCBs are behaving properly now. I finally received in the post yesterday a cheque for £273 from my local council as a refund of a Building Notice fee from March that I should not have been required to submit, because they have acknowledged I can self certify . Sadly, I am passing it onto my client although I did the work in recovering it.

Regards
Bruce

 

[rt1200]

I note that the document was written on 6th May 2011. I wonder where it's been hiding for the past 2.5 months.

It also seems less than totally definitive - still allowing an assessment to be made as to whether the 15% limit is exceeded or not. 15% itself is only a rule of thumb, as are all the 'guidelines' in the Building Regs.

And leaving some doubt as to which CPS does cover Part A or not seems inadequate. Part P schemes are a CPS without any doubt even if the double-talk around MCS accreditation says that they are not. Are there any PV installers who are not also in a Part P scheme?

The part that it does seem to clarify is that a Part A application is only required when strengthening work is carried out to a roof and that work is based on an engineers report that is only required if the 15% limit is exceeded - and that any BR fee is based only on the cost of the strengthening work and not the total job cost. That, at least, is useful.

To be fair its been out there. Its just knowing there may be an implication and knowing where to look for guidance, which I guess is where the competence comes in. Please dont take that the wrong way -Im trying to be helpful.
I would forget all about minimum standards here and whether its 1% either side of 15% or not. We all know that Building regs are minimum requirements and many of us exceed them out of choice. The bottom line is this, the installer is responsible for ensuring the structure will take the loadings. If you install a PV array and the roof subsequently fails you may well find yourself liable for rectification works, which can be very expensive and potentially damaging to your good name. I believe the statute of limitations for contracts not under seal is 6 years?
Regards,

 

[Fitstart]

Is there something similar for Scotland?

I ask as a potential buyer of a Solar PV system, as I am getting conflicting information on Building Control requirements and whether the cost is related to the total cost of the installation or only the fittings for the panels.

 

[dansk]

That document has been in the members download area on NAPIT for a wee while.

 

[rt1200]

I note that the document was written on 6th May 2011. I wonder where it's been hiding for the past 2.5 months.

It also seems less than totally definitive - still allowing an assessment to be made as to whether the 15% limit is exceeded or not. 15% itself is only a rule of thumb, as are all the 'guidelines' in the Building Regs.

And leaving some doubt as to which CPS does cover Part A or not seems inadequate. Part P schemes are a CPS without any doubt even if the double-talk around MCS accreditation says that they are not. Are there any PV installers who are not also in a Part P scheme?

The part that it does seem to clarify is that a Part A application is only required when strengthening work is carried out to a roof and that work is based on an engineers report that is only required if the 15% limit is exceeded - and that any BR fee is based only on the cost of the strengthening work and not the total job cost. That, at least, is useful.

Ted I just read your reply again, (this time properly!), and would like to clarify something, mainly for others, please. Part A applies if you plan to increase the loading on a roof by 15% or more. I believe this is over the area of coverage per M2 and not total roof loading. Once the regs apply BC will ask for an engineers report. If he/she confirms the roof is ok, with calcs, to accept the additional load - OK. If it doesnt the work to upgrade the roof, once approved, may be inspected for conformity by BC. However, as the document alludes to, the roof and its constituent materials may not be of the best quality and it may have been altered in the past, or suffered decay, thus reducing it strength. Indeed, many roofs have already seen an increase such as a change in roof coverings E.G. from slate to concrete interlocking tiles. I see many roofs which are displaying subtle or even major signs of stress and this is before an Array is added. Therefore 15% or more and you MUST have the structure checked BUT, it would seem sensible to have the roof inspected if it is very close to 15% or if there are any concerns whatsover. For me concerns would include but not be limited to: any evidence of decay or infestation, any previous structural alterations such as dormers, loft conversions, removal of chimneys, replacement or removal of significant members, changes in roof coverings, signs of stress to either the roof itself or the building generally. I strongly believe that the persons undertaking site surveys on behalf of PV companies should be qualified, experienced, (in the building type), engineers or surveyors. I know many roofers who are excellent roofers but, with the greatest respect, they are not engineers or surveyors. I hope this is of some help to persons reading my original post with queries.
Regards

 

[rt1200]

Is there something similar for Scotland?

I ask as a potential buyer of a Solar PV system, as I am getting conflicting information on Building Control requirements and whether the cost is related to the total cost of the installation or only the fittings for the panels.

The regs in Scotland may be different. Quite often they are more demanding. Best ask your area building control officer. Regarding fees, again there might be a slight difference in Scotland but down here its based on the cost of the work - the roof structural upgrading work. It should be much less if its just to issue a cert saying the array conforms following an inspection. Most of their costs will be in looking at plans or specifications and site visits.

 

[Fitstart]

Many thanks, I am told it varies from region to region as well. In Fife they are trying to charge about £350! (For ticking a box). Money making exercise. (You still have to pay for a structural report on top of that).

 

[rt1200]

Many thanks, I am told it varies from region to region as well. In Fife they are trying to charge about £350! (For ticking a box). Money making exercise. (You still have to pay for a structural report on top of that).

Just because they say its this much doesnt mean you have to accept it as gospel. As long as your polite, you can challenge it. They should all be working to a fee structure and should be able to explain how they arrive at their fees. As I said before, BC are confused about this. They are NOT certifying the whole installation so the fees should not be based on the total cost - only a part.
Not sure if its the same up there but down here there are private companies undertaking the building control function too and it might be worthwhile calling them?
regards,

 

[Fitstart]

Thanks again. So far one potential installer has said I don't need a building warrant, another says I do and it will be £350 based on total cost, and a third says it will be less because it is just the part that supports the panels that it should be costed on. It is totally confusing to the consumer and BC.

 

[SRE]

Please see attached pdf guidance note relating to the structural assessment of roofs prior to fitting PV arrays and the requirement for Building Control Appproval, if you are not registered as a competent person/body in the CPS scheme. MSC is not CPS. I hope you will find this useful as it is fact and not just someones opinion!

In summary many if not most PV arrays will require a structural assessment of the existing roof, or the proposed new roof to ascertain that if it can safely take the loadings. Many local building control officers are struggling to come to terms with what this means and its implications. They are not competent themselves and will/should ask for a structural engineers report. Some appear to be confused and talk only of the electrical installation. Nevertheless, as you will see in the attachment, it does relate to structural stability. Under the CPS scheme a competent person would virtually have to be a structural engineer to properly assess.

The bottom line is that a structural engineer is required whether you are CPS or apply for Building control approval via a building notice. Incidentally, the cost of the LA approval is related to the work itself. NOT ALL the work - just that related to strengthening the roof, so in most circumstances it shouldnt be hundreds of pounds. View attachment 6798View attachment 6798

This has been on the forum a couple of times and the attached document is flawed - it's been pointed out to LABC who issued it but they've ignored the inaccuracies. CLG, LABC and the CPS operators met on July 11th and agreed that CPS does cover Part A, C where appropriate and of course P. Our BC officers are now refunding all the householders that they have charged for BC inlcuding the LA that kicked all of this off a couple of months ago. That's not a matter of opinion but a result of a meeting of all relevant parties a fortnight ago.

How the CPS operators assess installers is a different question, watch out those of you who have looked at a roof and given it the ok without having the calcs done or an assessment by a structural engineer - on surveillance visits I reckon they are going to be asking for proof going back several months.

 

[rt1200]

This has been on the forum a couple of times and the attached document is flawed - it's been pointed out to LABC who issued it but they've ignored the inaccuracies. CLG, LABC and the CPS operators met on July 11th and agreed that CPS does cover Part A, C where appropriate and of course P. Our BC officers are now refunding all the householders that they have charged for BC inlcuding the LA that kicked all of this off a couple of months ago. That's not a matter of opinion but a result of a meeting of all relevant parties a fortnight ago.

How the CPS operators assess installers is a different question, watch out those of you who have looked at a roof and given it the ok without having the calcs done or an assessment by a structural engineer - on surveillance visits I reckon they are going to be asking for proof going back several months.

SRE I would respectfully suggest that you may have confused the issue. (I did emphasise that individual BCO's are confused about this themselves also about when, if and how much to charge). Im not saying your wrong but its not the document that's the issue but its interpretation - what we are saying in summary seems to be virtually the same.

Please let me clarify further. The document clearly states that "CPS membership allows installers to assess whether compliance with Part A will be achieved". It also states, quite rightly that "not all CPS scheme operators encompass Part A issues". additionally it correctly quotes from Approved Document A which "gives guidance on achieving compliance with this aspect and suggests that additional loading to a roof structure would constitute a material alteration if the loading to the roof is increased by 15% or more". This is correct.

My point was that the vast majority of roofers and electricians are unlikely to be competent to assess the structural integrity of roofs and the effects of dead and imposed loading. This is the competence of a qualified structural engineer who's professional indemnity insurance covers them for such caculations and the provision of related advice. With this in mind I would repeat my previous advice, (the essence of the point I was trying to make), with which you appear to agree: "The bottom line is that a structural engineer is required".

Incidentally, if there is a structural failure as a result of additional loadings, and it can be shown that negligence occured because a proper assessment was not undertaken and a reasonable assessment would have been expected to have foreseen the likely consequences, its quite probable that the installer will be sued for damages. Furthermore, if a roofer or electrician, or structural engineer for that matter, assesses a roof for increased loadings and the roof subsequently fails they too are likely to be sued. The difference is that the structural engineer will/should have insurance to cover the liability. Lastly, forget surveillance visits for several months - your legal liability for damages remains for a minimum of 6 years. If others reading this are still unsure about these issues, dont ask your LABC, ask a solicitor.
Regards,

 

[rt1200]

It has been in the hands of all the Building Control Bodies and the registration bodies since then and is what was informing the views of the BCBs. I was slipped a copy in early Jun, but my registration body did not want to be seen to be publically releasing it as it was not theirs to release. It does irritate me when quasi public bodies that effectively we as the public have funded do not place stuff like this in the public domain.

But at least some BCBs are behaving properly now. I finally received in the post yesterday a cheque for £273 from my local council as a refund of a Building Notice fee from March that I should not have been required to submit, because they have acknowledged I can self certify . Sadly, I am passing it onto my client although I did the work in recovering it.

Regards
Bruce

Bruce
out of interest was the self certification you refer to for the electrical installation? Im assuming it is. Some of them really are confused! Asking for fees when they are not entitled and forgetting to advise when they should be. E.G Part A.
Regards,

 

[rt1200]

It has been in the hands of all the Building Control Bodies and the registration bodies since then and is what was informing the views of the BCBs. I was slipped a copy in early Jun, but my registration body did not want to be seen to be publically releasing it as it was not theirs to release. It does irritate me when quasi public bodies that effectively we as the public have funded do not place stuff like this in the public domain. <br>
<br>
But at least some BCBs are behaving properly now. I finally received in the post yesterday a cheque for £273 from my local council as a refund of a Building Notice fee from March that I should not have been required to submit, because they have acknowledged I can self certify . Sadly, I am passing it onto my client although I did the work in recovering it.<br>
<br>
Regards<br>
Bruce

<br><br>Bruce<br> out of interest was the self certification you refer to for the electrical installation? Im assuming it is. Some of them really are confused! Asking for fees when they are not entitled and forgetting to advise when they should be. E.G Part A. <br>Regards,<br>

 

[TMGL]

Thanks again. So far one potential installer has said I don't need a building warrant, another says I do and it will be £350 based on total cost, and a third says it will be less because it is just the part that supports the panels that it should be costed on. It is totally confusing to the consumer and BC.

FitstartIt was the case up until about 2 weeks ago that certain councils (Scottish borders for example) insisted on a building warrant. However the building standards director for Scotland has confirmed that a building warrant is not required for solar pv unless i) strengthening work is to be carried out to the roof or ii) the building is above a certain height (can't remember exact height but normal 2 storey building will be fine).Most pv installations in Scotland will therefore not need a building warrant but your installer should confirm that i) and ii) above do not apply in your case.Hope this helps.

 

[BruceB]

<br><br>Bruce<br> out of interest was the self certification you refer to for the electrical installation? Im assuming it is. Some of them really are confused! Asking for fees when they are not entitled and forgetting to advise when they should be. E.G Part A. <br>Regards,<br>

I started out as electrical with NAPIT, but for a year have been MCS registered with Napit, so the self certification was for everything. Napit have just changed the 'rules' of their scheme which now make it clear in words of few syllables that MCS registered members can self certify under building regulations.
Regards
Bruce

 

[Fitstart]

FitstartIt was the case up until about 2 weeks ago that certain councils (Scottish borders for example) insisted on a building warrant. However the building standards director for Scotland has confirmed that a building warrant is not required for solar pv unless i) strengthening work is to be carried out to the roof or ii) the building is above a certain height (can't remember exact height but normal 2 storey building will be fine).Most pv installations in Scotland will therefore not need a building warrant but your installer should confirm that i) and ii) above do not apply in your case.Hope this helps.

Excellent News! - I shall of course get a structural survey done. Hopefully this information has filtered through to Fife.

 

[mapl_co_uk]

We are structural engineers undertaking these assessments - about 50% of domestic roofs need some form of strengthening to resist not only the weight but the uplift forces generated as wind passes over the panels.

Building Control in England & Wales have recently confirmed that assessments are needed and have guided building control departments accordingly. The MCS accreditation bodies are also starting to ask for evidence of competent structural advice when assessing or annually auditing installers, so that their schemes can be considered CPS and allow self-certification. But if you self certify without site specific checks, you are potentially creating a huge future liability! Put a check from us on file, so you are covered by our insurances if there is a structural problem!

 

[SRE]

Where are you based? We've done structural surveys for every install since we started and have had a failure rate of approx 10% not 50%. Ours have been mainly in 50's - 70's builds, newer and older seem to be coming through ok.

 

[mapl_co_uk]

Assessments have been across southern England and covered a vast range of property ages and forms of construction. Even trusses can have issues, although urban myth suggests a trussed roof is automatically OK!

Most fails are due to uplift when applying the BRE489 loads to the roof.

 

[SRE]

Must be different build quality in the North, best not to make sweeping generalisations about failures I find

 

[Fitstart]

FitstartIt was the case up until about 2 weeks ago that certain councils (Scottish borders for example) insisted on a building warrant. However the building standards director for Scotland has confirmed that a building warrant is not required for solar pv unless i) strengthening work is to be carried out to the roof or ii) the building is above a certain height (can't remember exact height but normal 2 storey building will be fine).Most pv installations in Scotland will therefore not need a building warrant but your installer should confirm that i) and ii) above do not apply in your case.Hope this helps.

If you do have the source of that statement from the BS Director could you possibly give me a link just in case I need to quote it to Fife Council - thanks.

 

[TedM]

I still think the basic issue here is the difference between what the legislation says - which is quite categorical that a member of a (named) CPS can self certify their main work and any associated building work - and the interpretation of that by LABC.

I don't see that the two tie up.

Whether MCS is or isn't a CPS is not material (and seems to have been included as a red-herring) as it is not one of the named CPS's in the legislation in any case.

 

[TedM]

Installers claim victory in solar planning battle - 26 Jul 2011 - News from BusinessGreen

 

[BruceB]

I find it surprising that 50% of roofs need reinforcement from the ones I have seen.

I also would be interested to know from the structural engineers here whether BRE489 is overestimating the wind uplift? The reason I think it may well be is that the assumption to come to Cp.net of -1.3, the wind uplift coefficient for panels <300mm from the roof surface on page 5, is that the panels are touching and so effectively impermeable and working like a single large aerofoil. In fact with the schuco mounting system I have been using there is a space of about 22mm around the edge of each panel which would impair the build up of any pressure differential and would destroy the lift generated by the array acting as an aerofoil.

Regards
Bruce

 

[rt1200]

We are structural engineers undertaking these assessments - about 50% of domestic roofs need some form of strengthening to resist not only the weight but the uplift forces generated as wind passes over the panels.

Building Control in England & Wales have recently confirmed that assessments are needed and have guided building control departments accordingly. The MCS accreditation bodies are also starting to ask for evidence of competent structural advice when assessing or annually auditing installers, so that their schemes can be considered CPS and allow self-certification. But if you self certify without site specific checks, you are potentially creating a huge future liability! Put a check from us on file, so you are covered by our insurances if there is a structural problem!

I know you are in Southern england but where abouts? You can send a confidential email via the forum if you wish?
Regards,

 

[rt1200]

Installers claim victory in solar planning battle - 26 Jul 2011 - News from BusinessGreen

Thanks TedM.

This link underlines one of the points I was initially making. That is MSC is not CPS in relation to structural integrity. I have copied and pasted a paragraph from the link here for others -
"The government's revised documents make it crystal clear that customers using companies ... which are members of the Competent Person Scheme and MCS approved can allow us to self-certify all aspects of installation including roof structure,"
If anyone is willing to, I would be grateful to learn what indemity insurance PV installers have, specifically for structural assessment of roofs, who is the scheme underwriter and how much it costs. Also, what CPS scheme they operate under and does this require any formal training or qualifications? I have heard of a City and Guilds qualification which may be accepted by some CPS schemes.

 

[rt1200]

FitstartIt was the case up until about 2 weeks ago that certain councils (Scottish borders for example) insisted on a building warrant. However the building standards director for Scotland has confirmed that a building warrant is not required for solar pv unless i) strengthening work is to be carried out to the roof or ii) the building is above a certain height (can't remember exact height but normal 2 storey building will be fine).Most pv installations in Scotland will therefore not need a building warrant but your installer should confirm that i) and ii) above do not apply in your case.Hope this helps.

Thanks for this. Its interesting to know how things differ in Scotland, particularly for companies operating near the border I guess!! Sounds sensible - if your going to load a roof, undertake a competent assessment and if no strengthening is required thats it - no fees for checking it, particularly when no works are required.

One thing Im not sure about is if the "competent person" is competent enough to undertake structural calculations in the first place - surely they would be as equally competent to design, oversee and check the solution? Thats what I would expect from a competent person and therefore why the need for Scottish building Regs to apply at all? A fair point?

 

[ScottishKev]

View attachment Minor domestic work guidance v2.pdfI have dealt with Fife Council in the last week. Fife Council insist on a building warrant when installing PV Solar panels. Fife Council insist on a structural survey when fitting more than one row of PV panels on a fram above the roof, i.e. adding to the weight - see attached document 'Minor domestic work guidance v2.pdf'. I guess that Fife Council have had sight of the study by BRE that recommends a structural survey when installing more than one row of panels - see attached file 'BRE_Study.pdf'.View attachment BRE_Study.pdf I would say that having a structural survey is good practise and every install should have one.

 

[Fitstart]

OK on the structural survey Kev, I would be doing that anyway. However Fife should now not require a Building warrant for Solar PV unless strengthening work is required on the roof, as per the recent communication to all councils:

​The key part is:

8 July 2011

Our ref: A1616295 Dear Chief Executive

The Building (Scotland) Act 2003
Domestic Microgeneration – Installation of Solar Photovoltaic and Solar Thermal Equipment on a House

I am writing to all local authorities to advise on procedures for dealing with the installation of solar photovoltaic (PV) and solar thermal equipment on existing houses. This is to promote a uniform approach when considering the structural impact of the work on the existing building, and when a building warrant is required for the work.

The intention of this advice is to clarify that a building warrant should not be required when the existing structure of a one or two storey house is capable of supporting the solar PV and solar thermal equipment. However if the existing structure is not capable, and strengthening is needed, a building warrant is required.

This advice is limited to type 1 of schedule 3 of the Building (Scotland) Regulations 2004 as amended which covers houses with a storey at a height of no more than 4.5m. Supporting information is included in annex A.

I would like to take this opportunity to thank you in advance for your local authority’s co-operation in this matter.

Yours sincerely

Bill Dodds
Head of Building Standards

 

[ScottishKev]

OK on the structural survey Kev, I would be doing that anyway. However Fife should now not require a Building warrant for Solar PV unless strengthening work is required on the roof, as per the recent communication to all councils:

​The key part is:

8 July 2011

Our ref: A1616295 Dear Chief Executive

The Building (Scotland) Act 2003
Domestic Microgeneration – Installation of Solar Photovoltaic and Solar Thermal Equipment on a House

I am writing to all local authorities to advise on procedures for dealing with the installation of solar photovoltaic (PV) and solar thermal equipment on existing houses. This is to promote a uniform approach when considering the structural impact of the work on the existing building, and when a building warrant is required for the work.

The intention of this advice is to clarify that a building warrant should not be required when the existing structure of a one or two storey house is capable of supporting the solar PV and solar thermal equipment. However if the existing structure is not capable, and strengthening is needed, a building warrant is required.

This advice is limited to type 1 of schedule 3 of the Building (Scotland) Regulations 2004 as amended which covers houses with a storey at a height of no more than 4.5m. Supporting information is included in annex A.

I would like to take this opportunity to thank you in advance for your local authority’s co-operation in this matter.

Yours sincerely

Bill Dodds
Head of Building Standards

Thanks for this - I will forward to fife Council. I have just sent my cheque off this morning - I will let you know how I get on.

 

[Fitstart]

You are welcome, hope it goes well.

 

[ScottishKev]

You are welcome, hope it goes well.

Have just heard back from Fife Council - they will refund any fees for building warrants received after the 8th July!! Getting a very good service from Fife Council Building Standards And Safety - very quick.

 

[Fitstart]

That's great news, glad they are on the ball.