{"id":730,"date":"2024-05-20T14:20:15","date_gmt":"2024-05-20T13:20:15","guid":{"rendered":"https:\/\/blog.hslracing.com\/myhome\/?p=730"},"modified":"2024-05-20T16:25:21","modified_gmt":"2024-05-20T15:25:21","slug":"solar-and-storage-building-control-and-structural-calculations","status":"publish","type":"post","link":"https:\/\/blog.hslracing.com\/myhome\/2024\/05\/solar-and-storage-building-control-and-structural-calculations.html","title":{"rendered":"Solar and Storage &#8211; Building Control and structural calculations"},"content":{"rendered":"<p>I applied and paid for Building Control notification of my solar installs back in November 2023.<\/p>\n<p>Having already installed and commissioned my system, I was a little concerned that I would receive a telling off from the Building Control officer when he eventually came around to inspect the work in that I should have had them round before starting.<\/p>\n<p>I booked a visit for Wednesday morning and in the days leading up to this visit I also decided to have a go at some structural design calculations to see if they would be complaining about the strength of my various roof structures.<\/p>\n<p>The <a href=\"https:\/\/www.timberbeamcalculator.co.uk\/\">Timber Beam Calculator<\/a> has a breakdown of all the various calculations based on roof type, along with some demo worked examples, so I decided to build a spreadsheet to model the calculations.<\/p>\n<p>The worked examples assume a dead load of around 0.5kN\/m2 of roofing structure (excluding the joists), this theoretical roof will be something like roofing felt, plywood, joists, plasterboard and skim.<\/p>\n<p>The joists are omitted because the values associated with them are calculated separately based on actual size and grade of timber and then added into the calculations.<\/p>\n<p>I have two different roof compositions, one for the &#8216;Garage&#8217; roof and one for the &#8216;Office&#8217; roof.<\/p>\n<p>The Office roof is built as follows:<\/p>\n<ul>\n<li>EDPM<\/li>\n<li>GRP (old fibreglass covering)<\/li>\n<li>18mm OSB 3<\/li>\n<li>18mm marine plywood<\/li>\n<li>50mm Kingspan insulation<\/li>\n<li>18mm marine plywood<\/li>\n<li>63 x 220mm joists on 400mm centres, max clear span 2000mm<\/li>\n<li>9.5mm plasterboard and skim<\/li>\n<\/ul>\n<p>I then added in the load for the solar panels and associated framing to give a total dead load (excluding the joists) of 0.77kN\/m2<\/p>\n<p>The Garage roof is slightly different:<\/p>\n<ul>\n<li>EDPM<\/li>\n<li>GRP (old fibreglass covering)<\/li>\n<li>18mm OSB 3<\/li>\n<li>18mm marine plywood<\/li>\n<li>150mm Kingspan insulation<\/li>\n<li>18mm plywood<\/li>\n<li>50 x 150mm joists on 300mm centres, max clear span 2600mm<\/li>\n<li>12.5mm plasterboard and green glue<\/li>\n<li>12.5mm plasterboard and skim<\/li>\n<\/ul>\n<p>I then added in the load for the solar panels and associated framing to give a total dead load (excluding the joists) of 1.03kN\/m2<\/p>\n<p>This then allowed me run all of the various calculations for each of long, medium and short term loading for bending, shear and deflection.<\/p>\n<p>Fortunately, both roof structures passed, even with the additional solar load, the closest worry was the short term load deflection on the Garage roof which came out as 58.2% but still well under the allowable 100% figure.<\/p>\n<p>Office design summary<\/p>\n<p><a href=\"https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.21.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-731 size-medium\" src=\"https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.21-300x78.png\" alt=\"\" width=\"300\" height=\"78\" srcset=\"https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.21-300x78.png 300w, https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.21-1024x266.png 1024w, https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.21-768x199.png 768w, https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.21-809x210.png 809w, https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.21.png 1256w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p>Garage design summary<\/p>\n<p><a href=\"https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.34.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-732 size-medium\" src=\"https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.34-300x78.png\" alt=\"\" width=\"300\" height=\"78\" srcset=\"https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.34-300x78.png 300w, https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.34-1024x265.png 1024w, https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.34-768x199.png 768w, https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.34-809x209.png 809w, https:\/\/blog.hslracing.com\/wp-content\/uploads\/sites\/6\/2024\/05\/Screenshot-2024-05-15-at-12.52.34.png 1252w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p>When the building control inspector finally arrived, I immediately confessed that this was not really a pre-install visit as I had already completed the installation and commissioned it.<\/p>\n<p>Turns out he was absolutely fine with this and even happier after I provided him with a full explanation of the installation and my qualifications as an electrician and Enphase certified installer.<\/p>\n<p>I explained the roof structures of both flat roof areas, along with their histories concerning the different layers and said I would supply him with my calculations that he would in turn pass on to his structural engineer.<\/p>\n<p>I also explained about how this was an all AC installation and that the only DC element was between each panel and its microinverter at around 50V.<\/p>\n<p>I then explained all of the various isolators and cable types used in the installation and he was more than happy with the design and explanations.<\/p>\n<p>He inspected the flat roof areas as well as the inside of the pre-fab garage and was satisfied that everything was more than capable of meeting the building control requirements.<\/p>\n<p>I pointed out the extra load spreaders and feet that I had installed to further reduce the point loading under the ballasted areas.<\/p>\n<p>In all a very pleasant experience and hopefully I should receive my Part A notification from the council stating that all is good from a structural stand point in due course.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I applied and paid for Building Control notification of my solar installs back in November 2023. Having already installed and commissioned my system, I was a little concerned that I would receive a telling off from the Building Control officer when he eventually came around to inspect the work in that I should have had&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[9],"class_list":["post-730","post","type-post","status-publish","format-standard","hentry","category-uncategorised","tag-solar"],"_links":{"self":[{"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/posts\/730","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/comments?post=730"}],"version-history":[{"count":2,"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/posts\/730\/revisions"}],"predecessor-version":[{"id":734,"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/posts\/730\/revisions\/734"}],"wp:attachment":[{"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/media?parent=730"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/categories?post=730"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.hslracing.com\/myhome\/wp-json\/wp\/v2\/tags?post=730"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}