Pseudomax Posted January 21, 2018 Share Posted January 21, 2018 Hi My questions/advice needed relate to an extension that I am finishing off. I have 2 RSJ's spanning about 3m and the edge of them is exposed to the external elements. The whole extension will be rendered with a monocouche render to match the rest of the house. You may question why there is a mixture of brick and block ... well unfortunately the first bricklayer let me down significantly, so I had to ask another guy I knew from a while before (but was not available when I originally started the project) to complete the work (hence the change from facebrick to render). My question/concern is that although the RSJ's are painted in a red primer, I am concerned that they will rust over time causing the external render and brickwork to crack. There are no fitted cavity trays, but there is a damp membrane a little further up the cavity that directs water from the internal brickwork skin to the external brickwork. There even appears to be some early discolouration that may be some surface rust. So before I cover everything ... am I being overly paranoid and if not then what should I use to protect? Also, even if I paint/cover the edges exposed, will the weather/rain penetrate the first skin of bricks/blocks and cause rust to continue? I was thinking of putting cement board up across the whole frontage and then rendering? But I am not even sure if the render itself will prevent the water ingressing to the RSJ's? (I will be having some bifold doors under these RSJ's) Thanking you all in advance! Link to comment Share on other sites More sharing options...
nod Posted January 21, 2018 Share Posted January 21, 2018 It should be hot dipped if it is exposed to the elements Link to comment Share on other sites More sharing options...
Pseudomax Posted January 21, 2018 Author Share Posted January 21, 2018 Thanks ... although that is a bit late to do now ... it was painted in red oxide ... so it wasn't bare metal ... Link to comment Share on other sites More sharing options...
nod Posted January 21, 2018 Share Posted January 21, 2018 10 minutes ago, Pseudomax said: Thanks ... although that is a bit late to do now ... it was painted in red oxide ... so it wasn't bare metal ... Red oxide is ok for internal But not external BC will pick it up I would be inclined to sand the redoxcide off and hand paint galvanising paint on it I re used two simalar beams on our garages and bought the paint from a boat yard supplier I figured if it was for the hull of boats it would be ok to stand a bit of rain twelve month on it looks like it has just been painted I can’t remeber the name of the paint I think it was about £20 for a lite Which did two coats to two 4 mtr beams I boat it from Preston docks marina shop They May have a website Hope this helps Gary Link to comment Share on other sites More sharing options...
Onoff Posted January 21, 2018 Share Posted January 21, 2018 3 minutes ago, nod said: Red oxide is ok for internal But not external BC will pick it up I would be inclined to sand the redoxcide off and hand paint galvanising paint on it I re used two simalar beams on our garages and bought the paint from a boat yard supplier I figured if it was for the hull of boats it would be ok to stand a bit of rain twelve month on it looks like it has just been painted I can’t remeber the name of the paint I think it was about £20 for a lite Which did two coats to two 4 mtr beams I boat it from Preston docks marina shop They May have a website Hope this helps Gary Zinga, Galvafroid? Link to comment Share on other sites More sharing options...
Pseudomax Posted January 21, 2018 Author Share Posted January 21, 2018 2 minutes ago, nod said: Red oxide is ok for internal But not external BC will pick it up I would be inclined to sand the redoxcide off and hand paint galvanising paint on it I re used two simalar beams on our garages and bought the paint from a boat yard supplier I figured if it was for the hull of boats it would be ok to stand a bit of rain twelve month on it looks like it has just been painted I can’t remeber the name of the paint I think it was about £20 for a lite Which did two coats to two 4 mtr beams I boat it from Preston docks marina shop They May have a website Hope this helps Gary Cheers Gary ... very much appreciated! I will certainly take your advice and do this! Obviously the top of this is already holding all the brickwork up, I assume that this won't be a problem, otherwise should I be applying some waterproofing to the brick face externally before I render it? If so any suggestions? Main concern would be damp that sits on top of the steel from damp brickwork ... Graham Link to comment Share on other sites More sharing options...
ProDave Posted January 21, 2018 Share Posted January 21, 2018 7 minutes ago, nod said: I think it was about £20 for a lite Which did two coats to two 4 mtr beams I boat it from Preston docks marina shop Which probably means you could have got it half the price elsewhere. Chandler's are not renowned for being cheap places to buy stuff. Link to comment Share on other sites More sharing options...
Ian Posted January 21, 2018 Share Posted January 21, 2018 (edited) @Pseudomax another, more expensive option, would be strip off the existing paint on the u/side of the beam and use cathode protection. Personally ive only ever used it for repairs to rusting rebar in old reinforced concrete buildings but I know it can also be used for protecting steel beams and columns. Mapei’s website shows the kind of thing I’m talking about. Scroll down to the bottom of the page for their products that can be applied to new steel beams. Edited January 21, 2018 by Ian Link to comment Share on other sites More sharing options...
nod Posted January 21, 2018 Share Posted January 21, 2018 54 minutes ago, Pseudomax said: Cheers Gary ... very much appreciated! I will certainly take your advice and do this! Obviously the top of this is already holding all the brickwork up, I assume that this won't be a problem, otherwise should I be applying some waterproofing to the brick face externally before I render it? If so any suggestions? Main concern would be damp that sits on top of the steel from damp brickwork ... Graham Yes you’ll be fine Graham Just clean off what you can see and give two coats I just used a grinder It doesn’t need to be pretty Link to comment Share on other sites More sharing options...
nod Posted January 21, 2018 Share Posted January 21, 2018 51 minutes ago, ProDave said: Which probably means you could have got it half the price elsewhere. Chandler's are not renowned for being cheap places to buy stuff. Not half Dave They have a little cafe there Simalar prices to dining out Good stuff for 20 quid though Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now