jamieled

@zoothorn due to my cockup I ended up with a load of non-waterproof chipboard exposed for weeks this summer. Water was pissing through the gaps, but it all dried up fine. You'll be fine for a few days for sure.

@Thedreamer we just used a couple of universal handsaws. Apparently you can use a recip saw with a cement blade but we didn't have one and weren't keen to shell out. Obviously a bit slower, but then it allows you to catch any mistakes before they go too far!

@Cpd thanks, your advice elsewhere on the forum was invaluable as it applies to this stuff just as much as the traditional sheeting.

I'm posting this as a single blog entry for a number of reasons. One as it's the biggest bit of work we've done without professional help. Two as sheet roofing seems to be a topic of interest on BH and three because this stuff was hard going, with minimal information available on fitting guidance, so hopefully this might help others. We are using eternit profile 6 sheet roofing. It is fibre cement board and we initially chose it due to some perceived benefits over wriggly tin (principally acoustics, condensation management and durability). Cost wise it seems to come out roughly similar (from what I could tell). One of the biggest differences is in weight. Each cement board sheet is in the order of 55kg. All 54 were manhandled on to the scaffolding, and the roof. Without doubt this is the biggest downside and I'd strongly recommend anyone considering using this stuff to be sure they have a way of moving it safely. Another challenging aspect is the sheet thickness. At around 7mm thick, this means potentially 28mm thickness where 4 sheets overlap. To avoid this, the sheets are mitred, which is a pain to do accurately on a curved sheet. The profiled wavelength and amplitude is greater than on most metal sheeting which when combined with the sheet thickness makes neat fitting around velux quite hard, irrespective of the pre-planning we did. A profile 3 sheet is available which is more similar to traditional metal sheeting. This probably sounds highly negative, but we're pretty pleased with how it looks. We've had a few downpours recently and it's looking quite solid. Still a couple of small bits to complete, but nearly done. As to whether I'd use it again, jury's still out... While it's still fresh in my mind, the other things I'll note are: -there is a right and wrong way to overlap sheets which is not obvious in the eternit guidance. It's not crucial for weatherproofness, but it can make the roof appear bumpy if not done correctly. -eternit helpline was not hugely helpful, but the local reps were definitely worth speaking to and very useful. Anyway, the photos: Above shows the sheet overlaps, with the mitre clearly visible. When the top right sheet is added, this disappears. Above shows the sheet overlap in section, but it also helps illustrates the sheet thickness. Below are a couple of more general shots of the finished product.

@KimBI haven't heard of them and I work in the industry. However, that doesn't mean much in the grand scheme of things as I tend to work on larger scale flood risk jobs. If you can get some recommendations, all the better. As with all professional services, the key aspect is what you are getting for your money. Are you paying them simply to get an independent rubber stamp of something you already know? Or are they potentially going to inform your design? Flood risk assessments can sometimes give clients an answer they don't want, but a good consultant will be able to help steer you through any problems. A bad one will just write a report assessing the level of risk and leave it up to you as to what to do next. The single biggest area of disagreement is usually when a client expects a flood risk assessment to give a clean bill of health and it doesn't do that. If it were me, I'd want to know the scope of their work, will it completely deal with planning requirements, might you need to do any more complicated assessment if this one turns up something concerning etc...?

The OP is likely to be ok with this approach due to only 4 trees being of concern, but for the benefit of other readers in the future, be aware that felling a large number of trees prior to applying for planning may result in you falling foul of forestry legislation. There was a case in the Cairngorms recently where a developer did this and was prosecuted by the forestry commission (have changed their name now to something else).

We had a lot of trees on our plot - we took out about 80 mature spruce (on condition of replanting). As to the machine, it depends a bit on how you are going about the work. You can get some quite big root plates out with smaller excavators, but it takes a lot of messing about, and unless you already own a smaller machine is unlikely to be cost effective. A 13 ton Hitachi did ours. It depends a bit on the ground as to whether a jcb will work - it would have got stuck very quickly on our site.

If it's just Carbon reduction, then removing the richest 10% of the population would apparently reduce emissions by about half. Don't know how that translates to particulates though.

We're doing ours at the moment, and it's not been easy, even taking all the useful info on here into consideration. If you have the means to DIY, then do it. I'm surprised that professional roofers would do that.

@Visti, sorry to see that. Is it fibre cement board?

We had Hilti impact anchors at 600mm (offset) centres.

They have two different functions. One makes sure you meet building regs, the other designs you a structurally sound house. If you go against the SE advice, you are carrying quite bit of risk if anything goes wrong (even if it is unrelated to the topic of discussion).

I meant to add, this will all depend on the competence and experience of the developer-there are easily findable stories of those who don't bother and end up in trouble. You can insure against this risk on big developments, I can't imagine the premiums being cheap though!

My experience of larger (non-residential) development is that there is often quite a bit of investigation work prior to construction, some of it intrusive, some of it not. It is expensive by the standards of self builders but still proportionate when you consider the overall costs.

There's been a concerted effort to try and move away from return period expressions of event probability as it tends to cause the EA some problems. However, exceedance probability type statements aren't often easily understood either so there's no easy answer and the return period is still commonly expressed. FWIW, I think fz3 is 1% or greater chance of flooding, and therefore it could be a lot more frequent than that. I suppose it might also depend on the nature of the risk - culvert and bridges backing up and causing flooding often have more to do with debris accumulation than the probability of the storm event itself. To the OP - the above is a bit academic, but my main point would be not to take any assessment of risk at face value! FZ 3 is split into 2 categories by the local authorities, 3a and 3b and this is not (I think) shown on EA maps, but does determine acceptability.

Forget the 'it's never flooded in living memory'. Flood risk is usually defined using probabilistic estimates of flood rarity which are well beyond living memory. For example flood zone 3 is a 1% exceedance likelihood, or, to put it another way, an event that is likely to occur on average, once in every 100 years. There are a couple of things you could consider. The flood maps vary in quality depending on where you are, as the underlying models also vary depending on whether there has been a need to recently update them. This is difficult to determine from the online mapping, but it might be that you're not really in flood zone 3! Only a review of the models would tell. Secondly, as others have mentioned, there are potentially creative ways around it. If you are only just within the flood zone, it may be that levels and velocities are low, so you can get away with a minimal amount of engineering. Unless you have detailed knowledge, it may prove tricky getting permission, but worth seeing how far you can get and understanding as much as you can before engaging anyone else.

You can buy these: https://shopping.rspb.org.uk/bird-silhouettes-window-stickers.html?utm_source=https://ww2.rspb.org.uk/birds-and-wildlife/read-and-learn/bird-watching/bird-behaviour/stop-birds-flying-into-windows&utm_medium=page-promo

At this scale, your gut might be the best bet. There are a variety of methods for runoff calculation, but at the small scale blockage risk usually results in up sizing culverts, drains etc by quite a bit. The specific local conditions in your field will have a big impact on runoff coefficients. Is there anything you can do to alter the direction of runoff if your chosen drain size is exceeded on occasion?

I start our roofing tommorow. We have mesh to install as per @Visti describes, although I have no eaves foam fillers, just a closure piece to allow a ventilation gap.

I am using eternit profile 6 sheeting. Rather than foam strips, I have eternit eaves closure pieces which will prevent wind driven rain, but allow ventilation as they overhang the sarking slightly (not that easy to explain).

Cheers @Visti, very useful!

Has anyone else got examples of ventilated firestop detail for a timber clad house? Either proprietary intumescent barrier or something else? Could use some inspiration.

Water companies can work out quite cheap for testing due to the volume of samples they work with. I'm not sure if all companies accept samples commercially, but Scottish Water were around £50 a sample for what I needed to test. As noted above, they gave me the prepared bottles and labels.

I am in the process of sorting something similar for our cladding, albeit for slightly different reason. As we have 1.5 storeys, we need a firestop at half height, and I have selected to insert a profiled cill/flashing on top of the firestop, to drain anything behind the 1st floor cladding. I'm getting some manufactured by planwell. They will stick out in front of the cladding by about 35mm. This is sort of arbitrary, because the cills/flashings are manufactured in fixed dimensions but I figured it should be enough.

@Ed Davies,That's right, maybe 15-20 miles from Beauly.