Karl Harrison Landscapes Ltd
Forum Replies Created
-
HI Craig
Good question, you may adopt a different design and run the decking away from the parallel instead of with it. This way it appears level against the house/wall but isn’t.
By having a run off across the boards may seem a sensible idea and in some cases its acceptable, and some not.
If the boards have a flat surface and they are your normal timber then they may cup which will cause the retention of water… in the cases of Lignia, Accoya and Kebony which shouldn’t pose an issue as these materials don’t cup.
I can’t comment for all composites but I know the Enhanced Grain boards from Millboard are slightly curved on the surface across the board so this is a great solution. There are many composites the don’t recommend this in their installation Manual…
What do you recon?
As Millboard is premium product anyway I see this as an enhanced and more saleable product.It may be more expensive option for materials but I am sure with the increased span (1.7m) there will be less support posts, I am not sure on pricing yet but there will certainly be a reduction in labour as a trade off.
For commercial project I see this as quite a revelation… it’ll get specified for sure
Nice list and a sensible presentation, but whilst these species are harder, appear durable but what about consideration for the ability of these species to perform in different areas of the world.Â
I have seen many of these tropical species underperform with regard to stability. With the exception of Ipe, the others certainly need a thicker material to maintain performance in stability. if this is not achievable due to limited supply then consideration should be for tighter joist layout (300mm C) and also much bigger fixings (min 5.5mm x 75mm)
There is far too much bad advice proffered to Landscapers and Contractors regarding these specialist materials… there should be much more information out there.
As long as it is over 750 Kgs Cubic Metre then yes… younger and less dense teak, although Tectona Grandis, it may not have developed the preservation oils that older trees have.Â
It is Durability class 1… so is Accoya®… but Accoya®is warranted for 50 years against rotting above ground… now that takes some beating!
There are other modified timbers that are being used for similar high end installations of course, such as Accoya®, Kebony® and Lignia®
Whilst I do very much like Cumaru as an alternative timber for Decking I do see limitations for its use in the UK.
Most contractors think they know best as assume all timber for decking is equal… we know that it isn’t. When using Cumaru as decking in the UK because we go from soaking wet to bone dry and of course plus 40 Deg C to -15 deg C we suffer from massive expansion and contraction issues.
Due to these climatic conditions I recommend only using Cumaru at 28 or 36mm thickness when used as hardwood decking – I also recommend a minimum of C25 and in section of 150 x 47 as structure. I also would insist on max centres of 500 and using predrilled and countersunk holes for fixing with 75mm screws, stainless of course. Anything less and your timber will move and snap the heads off… pretty much the same as Bankira (Yellow Balau).
Sanded or treated with Owatrol Prepdeck, NeTtrol and then soaked in either D1 or Textrol Exterior decking oil.
Do the compared to Teak or Ipe I would say, No, Cumaru is not the best decking material.
Â
I spoke to TRADA yesterday and they said that the decking manual will be EC5 updated in mid 2018
#justsayin Â
Hi Ivan
Iroko, all day long, looks great, affordable and achievable…
21 x 144 for the decking and 90 x 90 for the posts, the beams for the pergola could be 150 x 46 and the rafters/joists could be 100 x 46… ?
Looking forward to your design
cheers
karlÂ
Love the combination of the white fretwork panels, these mixed with the white Agapanthus.
I would remove the perimeter trim with the mitred corners, this looks a little dated… keep it straight… perhaps a powder coated white 6mm steel plate to the perimeter would look more stylish.
I recon you are right, it is in very bad shape, looks rather dangerous and to be honest if the image represents the quality of the timber I should possibly be condemned. What is the substructure like? If the structure is that bed then it should possible be replaced.Â
Maybe best to get something in writing and I would recommend taking plenty of images to safeguard you against any comeback.
Cheers
K
Jeremy Bevan said:
Unfortunately the client just wants us to make good for the time being, otherwise I alsways recommend Ipe for new decks. Prob go for a softwood then althoug it willstick out like a sore thumb, prob best to Netrol clean the whole deck then to stain/oil the whole thing. Do you agree?
Your first port of call would be TRADA, they promulgate the span tables and the latest standard is EC5 (EuroCode)
They also have a decking manual where you can find all of this information.
My thoughts on a comprehensive decking software are… As there are far too many decking types with too many variations in species, material, dimensions, fixing techniques… this would take an enormous amount of time and cost a fortune and just as soon as you launched it it would be almost out of date.
Consider one point alone and that being the posts/joists – would you opt for aluminium, steel, timber (hardwood or softwood) or HDPE (plastic), these all have many different fixing techniques and many different calculations…
Many of the American standards are not applicable in the UK, for instance the standard ledger board is usually fixed directly to the timber of the property with a standard flashing detail – this doesn’t apply in the UK as most buildings are brick or rendered block.
In the case of how wide, long, fixings etc one should really use a timber engineer or commission TRADA to provide the spec, this would then indemnify you should anything fail over time.
cheers for now
Karl
Wow that’s some old timber, its probably pine of some sort but I couldn’t be sure due to the rot and damage.
Do you need to know so you can replace like for like? If you are creating another decking I would recommend using a hardwood, Ipe or perhaps Iroko…Â
cheers
K
Hi Mark
I could write for hours on the complexities of decking structure design, have a look hereÂ
https://deckingnetwork.com/decking-resources/
There are post, beam, joist and decking span calcs that should be adhered to.
The main reason is if you don’t, whilst your completed project may look ok, in 6 months it will simply twist, buckle, snap screws and become unsafe, and you would have wasted your money.
In short 400 mm joist centres are only a small part of decking design. These numbers are there for a reason, 400 centres with pairs of countersunk holes for bugle head stainless screws are essential to prevent the timber from twisting, at 600 it will twist alright, snap the screw heads off too. The numbers are also integral to the loading the decking can withstand safely, 1.5kn is what is required and can only be achieved at 400 centres.
There are several pages on this site with advice for decking construction, if you are in need of advice, ask your questions and I am sure they will be answered…
Hey Carol
That’s great news, do list your products, images and news on the site. The site gets thousands of page views per month and the free promotion you’ll get is great
cheers
Karl
Carol Kay said:
Thanks for posting this, Karl. After 2 years and container loads of Fiberon boards sold into the UK market by SEAC, I suppose no news is good news. I say this in particular having read horror stories of inferior or hollow composite boards (I have link to the bad reviews but as they refer to a particular company or brand, I am not sure if I should include link here).
What we can offer here in response to your post, is that our company has had only one complain since we started selling Fiberon. The customer fedback that some of the ends were not cut at perfect right angle. The manufacturer confirmed that they received the same feedback. They immediately launched an investigation and found that it was because the cutters were not fastened securely in position. Action was swiftly taken to change the operators and the problem was solved. We have not received any feedback other than this one particular time.
I will let our installers and customers know of your forum should they wish to feedback, or more necessarily the good outlet to tell it all if they are not satisfied with the products. We, as supplier of Fiberon would be particularly interested to know too and to respond to complaints.
Carol Kay (Marketing Exec, SEAC Ltd)
