Soil pipe thru steel beam for loft?

[BBirds]

Good morning. Working on a loft conversion and need to figure out how to route water from the shower and toilet.

Someone has recommended that we can drill holes in the steel beams in the loft floor and route the shower and toilet waste through these holes.

Has anyone done that before? Will it cause issues with the integrity of the steel beam? Will it cause issues fixing future leaks in the soil pipe?

Grateful for all thoughts/views/experiences. Thx.

 

[Chuck]

Someone has recommended that we can drill holes in the steel beams in the loft floor and route the shower and toilet waste through these holes.

Were they a charter structural engineer? If not, that's who you need to consult.

The answer BTW if the steel is a structural element is almost certainly 'no'. Steels can, and are usually, designed with a relatively small safety factor because it's a predictable material.

 

[BBirds]

Thanks Chuck - that person was a neighbour who is a chartered surveyor but not the surveyor working on our project. I will check with our structural engineer but interested to hear from experience of this forum. I also found this link online so would value further thoughts from this forum:

Steel beam service hole | Smartbuild Engineering Ltd | UK

|ORDER ONLINE £195| Structural Engineer design calculations for service holes through steel beams. Calculations to Eurocode 3 or BS5950 by skilled Structural Engineers. Building Regulation compliant design accepted by all Building Control departments. Fast online service available.

www.smartbuild.uk.com

 

[gmartine]

As the ad above says, Building Control will usually need to be notified with a justifiable set of calculations.

 

[snowhead]

The surveyor neighbour is probably confusing seeing beams with holes already cut before installing and cutting holes after installing.

I used to work on commercial buildings and it was very common to see beams, on view after completion, with large holes in.
They're created with a clever method of cut and weld.

 

[B Bird]

Thanks all - my fault for being unclear - the loft has not yet been built so the neighbour surveyor said we could have the soil vent pipes go through the steel beams - he said in fact we could get steel beams with holes in them !

As such I’m interested in how often have people in this forum seen soil pipes going thru supporting steel beams of loft conversions? Is it common practice? Would people recommend snaking the spoil pipe between the joists of the ceiling below instead? Will they fit? What is “general practice” if there is one?

I’d value any and all thoughts.

 

[WC1]

The loft conversion will be done by a reputable contractor who will want to work off drawings from an architect / surveyor / engineer.
Planning and building control will also likely be involved. Theres all sorts of fire safety considerations for uk loft cons never mind soil pipes!
If you need steels, Holy or otherwise, they'll be specd by the engineer.
I'm afraid its not a DIY project.
(putting the bog in the right place is usually what makes the soil pipe "fit")

 

[B Bird]

The loft conversion will be done by a reputable contractor who will want to work off drawings from an architect / surveyor / engineer.
Planning and building control will also likely be involved. Theres all sorts of fire safety considerations for uk loft cons never mind soil pipes!
If you need steels, Holy or otherwise, they'll be specd by the engineer.
I'm afraid its not a DIY project.
(putting the bog in the right place is usually what makes the soil pipe "fit")

Thank you. Yes will be getting my surveyor to do all the specs and building control sign off. And also spoke to neighbour surveyor who confirmed that he was referring to using holey steels in the build, that are specifically designed for this purpose.

 

[gmartine]

The only thing about using "holey" steels is as you can see from the posted pic they are engineered to be extremely deep to compensate. If you have the room fine but more often than not for a loft conversion you are struggling to keep height, better to use clever/innovative design to route your outlets or get the steel co to cut the holes and reinforce where appropriate.

 

[Roy_66]

Thanks all - my fault for being unclear - the loft has not yet been built so the neighbour surveyor said we could have the soil vent pipes go through the steel beams - he said in fact we could get steel beams with holes in them !

As such I’m interested in how often have people in this forum seen soil pipes going thru supporting steel beams of loft conversions? Is it common practice? Would people recommend snaking the spoil pipe between the joists of the ceiling below instead? Will they fit? What is “general practice” if there is one?

I’d value any and all thoughts.

Have you looked at composite wood and metal web joists:


I've no experience yet of these. One point is you can't just saw them to length at any old point, so manufacture to required length.

Cheers,

Roy

 

[Martin Smartbuild]

Yes, you can cut holes in steel beams to route services, quite big ones sometimes but it all depends on how highly the beam is loaded, where in the span you need a hole and how big the hole is relative to the beam. Sometimes reinforcement is needed. A calculation check is needed to confirm adequacy - Building Control will usually request this. I wouldn't recommend going rogue and just drilling a large hole because you know it won't get spotted, do you really want to take on the liability and risk of structural collapse for the sake of a relatively cheap calculation by Structural Engineer?

There are some images on this page that give you an idea of achievable hole size and position:
Steel beam service hole | Smartbuild Engineering | UK - https://www.smartbuild.uk.com/steel-beam-web-opening-service-hole

For transparency this is my company. Many Structural Engineers arent familiar with the calculations needed to check holes in steel beams so we offer this as a service - many of our clients are Structural Engineers! We can work from the original Engineers calculations and drawings so don't need to visit site and therefore cover all parts of the UK (we're based in Brighton).