Fibreglass balcony questions

[jack]

Hi all

 

Made great progress today on the rails that will hold the frameless glass on our balcony.  It's so nice to be actually getting some bits and pieces done after so long!

 

Not long now and I'll be in a position to line and finish the balconies.  At the moment, they're just open joists.  We've been through several iterations with how the balconies will be finished.  At one point, we were just going to put open decking on the joists and allow water to drain through.  In the end, I've decided instead to fibreglass them.  

 

Very little rain gets in - there's a 1.1m high glass balustrade, an overhang, and sides, plus both balconies face away from the prevailing winds and weather.  I've therefore decided to just have a small discreet drain with only the minimum required fall towards it in case we ever have a massive storm from exactly the wrong direction.

 

I was considering buying one of those flat-roof kits you can buy by the square metre.  Before I do so, however, I have a couple of questions:

 

- Are such kits much of a muchness in terms of quality?
- It seems standard practice to use 18mm OSB3 - any better alternative?

- Tips for generating the falls to the drain easily?

- Any recommendations for suppliers?

- I'm considering using the topcoat as a wear layer.  I understand that you need to take this into account by using thicker fabric (600g) or doubling up on the standard stuff (450g), plus for grip I need to add something like slate granules to the topcoat.  Again, any thoughts on this approach versus perhaps building decking on top? 

- Any general tips or tricks I should know about DIYing this?  

 

@SteamyTea, am I right in thinking you have some experience in this area?

 

Thanks all 

[Nickfromwales]

Any chance of some pics as you progress please @jack ?

Be a good resource for anyone doing the same in the future. . 

[dogman]

And also suppliers of the glass etc. BC have conditioned ours as they want full details and although we have a few quotes real life examples are better.

[PeterW]

East Coast Fibreglass and CFS are two suppliers who I use. 

 

Both sell flat flat roof kits and have decent tutorials too online

[dogman]

Who is doing your glass balustrade? How did you fit it to satisfy your BC, i think part K protection from failing. 

[RichS]

I have a balcony planned into my build. Mine is over part of the garage so obviously must be watertight.

I intended to create the fall using firings on top of the joists to an outlet in the corner. 18mm OSB3 decking and then fibreglass covering. My thoughts for the balustrade, also glass, was to fit some male dowels to the decking/joists before the fibreglass and then slot the female balustrade posts over these at a later date. As for the finish surface I was thinking of tiles or similar.

[Alex C]

If you cut firings for falls and fit the osb 3 I have a local contact for doing the fibreglass who did a very tidy job at my place. Easiest way to cut firings is with a track saw. Interested in your balcony glass detail as well as I still need to get round to ordering that.

[RandAbuild]

I wonder about using fibreglass for the wear layer, but I suppose it depends how much you’re going to use it.

We’re planning to use EPDM on our balcony – anyone had experience of this? We are using porcelain tiles on telescopic legs. The rest is 18mm OSB and drainage to a single outlet using firrings under the OSB.

Would also be interested in the suppliers for and details of fixing glass balustrades

[Jeremy Harris]

The deck of a boat I owned years ago was just waxed gel coat with a bit of sand added, painted onto the roughened fibreglass deck with a roller.  I owned the boat for around 10 years and that surface was still in good condition when I sold the boat.  You could choose to paint the gel coat on a fibreglass roof with a tough floor paint if you wanted an alternative finish. 

 

I've only done one fibreglass flat roof, and that was on a friends garage, but it was pretty easy to do.  We used a kit from CFS that had prefabricated mouldings for the edges etc, which made the job a fair bit quicker.  You just need a dry day that's not too hot, and make sure you get the resin out of the mixing bucket and spread out onto the roof pretty quickly, as it starts to cure a lot faster when it's in a bucket, because of the heat build up.

[SteamyTea]

Mixing in dry sand (play sand is usually dry) to the flow/top coat is a common method.

 

As for thickness of material (the lay up), I would go for a minimum of 3 layers of 450g.m^-2 (used to be called oz and a half).  This should be about 3mm thick.

It is easy enough to put some extra layers on the high traffic areas if you feel you need to.

 

Most suppliers should be able to help you out with what you need.

 

I have never layed up GRP onto OSB, so reluctant to comment.  I do know that some MDFs can cause problems with delamination, as can some chip boards.  The only way to find that out is to make up a sample and see how easy it falls apart.

 

The main thing is to make sure everything is dry, and I mean really dry.  Damp is the killer for polyester resins.  If it goes cloudy when you first paint some resin on, stop.

Edited March 20, 2017 by SteamyTea

[Nickfromwales]

Plus one to just doubling up the layers. I did a 2 layered garage roof as the customer wanted to be able to walk on it when coming out of a upstairs French door. 

With 2 layers you could park a car on it.  

[jamiehamy]

I'm interested in this - our terrace is an EPDM roof. I'm currently trying to decide the best way to deck it - do I use tiles and adjustable supports or do I go for firrings and lay the composite decking across that. My timber merchant suggested that I would want to use something like cedar for the firrings to ensure they last as long as possible. The fall we have is 1/40 which was achieved by the joists themselves being set at that. I'm waiting on a price for the firrings which I should have tomorrow. I'll watch this and update with my prices if that might help in anyway. 

[RichS]

Jamie,

If you already have a 1/40 fall why do you need firrings??

[jack]

12 hours ago, RichS said:

If you already have a 1/40 fall why do you need firrings??

 

Presumably to counter the fall that already exists?  We're shortly going to be making the same decision as we have a large EPDM-covered terrace on top of our garage that needs covering.  Currently thinking slabs and adjustable pillars - not sure! 

 

22 hours ago, Nickfromwales said:

Any chance of some pics as you progress please @jack ?

Be a good resource for anyone doing the same in the future. . 

 

I won't be starting it until I've finished the balustrade on the main terrace, but sure, I'll take pics as I go along.

 

21 hours ago, PeterW said:

East Coast Fibreglass and CFS are two suppliers who I use. 

 

Both sell flat flat roof kits and have decent tutorials too online

 

Thanks Peter, they look good.  I'd already found CFS but will look into East Coast as well.

 

20 hours ago, dogman said:

Who is doing your glass balustrade? How did you fit it to satisfy your BC, i think part K protection from failing. 

 

For those asking about balustrades, we used Elite Balustrades.  There are several mounting options, and it's all DIY.  You might want to get your BC officer to confirm he's happy with whatever option you plan.  Our BC officer didn't ask for details beyond MBC's engineering drawings.  The architect had used Elite's mounting systems before and was asked for engineering calcs, which they had done pretty cheaply by an engineer.  

 

17 hours ago, RandAbuild said:

I wonder about using fibreglass for the wear layer, but I suppose it depends how much you’re going to use it.

 

We’re planning to use EPDM on our balcony – anyone had experience of this? We are using porcelain tiles on telescopic legs. The rest is 18mm OSB and drainage to a single outlet using firrings under the OSB.

 

We have Resitrix (a high-tech EPDM and modified bitumen based covering) on our roof and terrace.  Although I believe it's crap installation rather than the product's fault, having been through what we've been through I still wouldn't touch an EPDM-based roof covering with a barge pole.  I'd go for fibreglass if I were doing it again.  From everything I've read recently, it can be made as robust as you want it to be.  

 

The two balconies we plan to fibreglass are quite small, and off bedrooms, so won't get much foot traffic.

 

13 hours ago, SteamyTea said:

Mixing in dry sand (play sand is usually dry) to the flow/top coat is a common method.

 

As for thickness of material (the lay up), I would go for a minimum of 3 layers of 450g.m^-2 (used to be called oz and a half).  This should be about 3mm thick.

It is easy enough to put some extra layers on the high traffic areas if you feel you need to.

...

I have never layed up GRP onto OSB, so reluctant to comment.  I do know that some MDFs can cause problems with delamination, as can some chip boards.  The only way to find that out is to make up a sample and see how easy it falls apart.

 

Thanks for that.  Will look into multi-layer costs.  

 

From further research, it seems OSB3 is the only recommended substrate for fibreglass.