Structural Beam Coatings

[rmillener]

Hi All,

 

Views on what coatings external leaf structural beams should have? Am I right in saying there is no specific building regulation for the coating requirements for beams that will be sitting on external cavity walls to allow an opening for sliding doors?

 

I have been recommended to galvanise them, would this be the consensus of others? Or do I paint them in a coating instead which might be more cost effective.

 

Thoughts please?
 

Thanks

Rich

[Mr Punter]

Galvanised

[markc]

11 minutes ago, Mr Punter said:

Galvanised

+1 the cost is minimal and once done you pretty much forget about it.

[saveasteading]

Galvanised is safest but expensive.

Painting on site with the right, specialist paint is fine, as long as it is properly done (esp the bits which can't be seen) (which usually means you do it yourself or watch full time).

£50 / tin of Ruberoid etc. Plus labour of course.

Galvanising a beam specially....I'm guessing £200+ plus transport each way.

Likely to be a long and heavy beam, so maybe much more.

 

[Conor]

After spending half the weekend painting our balcony steels with two coats of bitimous paint, I'd stick my hand in my pocket every time and get them galvanised. The stuff is horrible. I've even left stains on the bath FFS.

[Pocster]

10 minutes ago, Conor said:

I've even left stains on the bath FFS.

🙄🙄🙄 we’ve all been there …

[Gus Potter]

5 hours ago, rmillener said:

Views on what coatings external leaf structural beams should have?

I would go galvanised. If you think about it Catnic and Keystone for example cold formed steel lintels are galvanised. Also they are probably over some nice door / windows.. the last thing you want is to spoil the effect.

 

SE wise.. external steels.. lintels for example can cause big problems if corrosion sets in.. it lifts the masonry.. not good.

 

Now galvanising comes at a cost. You can try and use special paints / treatments.. but avoid on a self build.. you find it's load of practical trouble. To do a good job you have to have the tools to prepare the steel to accept the coating.

 

Here is a thing.. you can drive down the galvanising cost.

 

First let's say you you live in.. Oxford.. your steel fabricator may have a choice of steel fabricators and they will have a choice of galvanisers. Some small.. some large. The big galvanisers have 6.0 m long or more galvanising baths. The smaller ones 4.0 m long.. they do say a lot of gates for farmers. Now if you have a 4.0 m long bath you can dip an 8.0m beam.. they dip one end at a time... called double dipping.. normally not good in a social context but good for us on BH! But I think you'll get the best price from the smaller galvanisers as the big baths are for big jobs.. not the self builder.

 

If you live in Scotland then your choice of local galvaniser's is limited., you can send it down south but you have the extra transport cost. You'll need to be a double dipper if you have long beams.

 

Now let's say you have a big house with a 9.0m beam, rules you out on getting competetive quotes from the small galvanisers. But you then say to your fabricator and SE.. can we split the beam into two or three?

 

If you do this you need to have beam connections.. but that can work in terms of cost.

 

For a bit of fun.. your big beam may be over an expensive set of bifold doors that are sensitive to deflections. If you start to splice the beam then the connections can move if say you use 16mm ordinary bolts.. they get drilled in 18mm hole. Thus you could get potentially 2.0mm of slip. Some SE's say bolts need to be high strength friction grip.. needs the right tooling and expertise.. comes at a cost and your local builder will not be keen and add on a bit to the price. It's not really the price.. builders and fabricators don't want the hassle.

 

A practical way is to say.. lets build the structure, load up say the roof.. get all the deads loads on the thing we can.. get the SE round for a look.

 

If I'm doing this.. for a bit of drama.. but also recognising that we are using the cheeper ordinary bolted connections that can slip I get a  heavy hammer and give the steel whack., some times ( not often)  you get a bang and it shifts.. but that is the bolts bedding in.  It's also a great way of heading off the really keen SE / BC checker.

 

Now we can measure up for the glass etc. Often we look to keep deflections over bifolds say to less than 4.0 - 8.0 mm .. nice to know that you have addressed some of the potential bolt slip.. and it gives you ammunition if the glass door folk start to argue later on if the doors start to stick.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[SteamyTea]

1 hour ago, pocster said:

🙄🙄🙄 we’ve all been there …

Yes, your skid marks are still showing.