loft conversion steel beam locations

[rico_suave]

Hi, I have drawn some plans for a loft conversion but unsure of the beam positions.

I have put the steel next to and in between some window openings at the side of the lintels, only because the house is a single skin wall and because I need to drop the ceilings for height. Putting them horizontally would mean they go through next door. I do not think they would appreciate that.

I am also unsure about how the loft floor will react on the beams in the kitchen. I have done some calcs myself and think it would be ok but would rather get a 2nd opinion before I submit these to building control.


I look forward to your input.

Thanks

 

[freddiemercurystwin]

Are these proposals for your own house or are you being paid to produce these for someone?

 

[rico_suave]

they are for my own house

 

[freddiemercurystwin]

I'd employ someone to do your plans.

 

[^woody^]

I'm having trouble seeing where the beam is actually going - where is it on the floor plan or section?

And what's the relevance to the mention of the floor reacting on the kitchen beams - what part of the plan is this referring to?

A quick general comment - your loft floor noggin is incorrect (you need one centrally, not all over the place) and why are the new floor joists running that way in any case? If that is a complete new floor going from side to side of the house and not front to back, then you are losing your roof and wall bracing.

Your loft internal walls appear too thick

 

[rico_suave]

the steel beams run front to back of the house they are drawn in red, one is in the middle of two windows at the back and the other is offset from the front window. they will sit on the cavity walls
the plans have been done like this because of a single skin party wall I cannot run beams side to side.
the loft internal wall thickness is just a guide dims are not exact
I know what you mean about the noggins, just thought it would be stronger putting them offset from one anther
with regards to the kitchen I have taken out the old external cavity wall to open it up and put two steels beams across, one on each wall. this is not on the plan as it was done last weekend. just unsure on how the point load will react from the loft rear beam onto the new kitchen beams

sorry for all the confusion

 

[freddiemercurystwin]

the plans have been done like this because of a single skin party wall I cannot run beams side to side.

Do you mean the party wall is 100mm thick or 215mm thick? Have you got a section/details/photos showing how your roof is supported at present? Typically there is a purlin on each side and the new beams are placed beneath these (side to side) then the existing supports removed.
You know you'll need an engineer right?

 

[^woody^]

Sorry but things just aren't clear to me.

You probablly didn't want a critique of the drawing, but its just hard to see anything, and that means that it will be hard for the plan checker to see things and then you get it rejected or furhter drawings and detail is requested. So I would not know where to start with an answer to the actual question.

There is no section cut line to depict where the section is on the floorplan, and the use of too many lines and colours makes it hard to see the important structual things - everything is too busy with too much detail.

I'd suggest rotating the plans so that they align with the section so it can be seen where things are relative to each other. Also lose the "existing" floor plans and just have the proposed with the new work in thicker lines and demolished work as dashed or similar.

Take the garish colours off, and lose all those noggins - just put a text note. Highlight the structural walls on the joist plan.

The lines are all coming out different thicknesses and shades. Standardise on one for new and one for existing. Take the plaster line off, that double line is confusing and you don't need it at 1:50

Use centre lines for the beams and a dashed outline

Take the furniture off

The floor thickness in the section is too narrow, and there is no way a steel beam will fit in it, so how is that going to work? You probablly need a part section through a beam too.

Most of all, I'd seriously reconsider the floor and beam layout. Put beams in the party walls as otherwise you will be in difficulties with the roof triangulation and bracing, and how are the purlins going to be supported?

 

[Ian H]

There's a place near you called Boarshurst who design lofts, could be worth you popping in there for a chat.

I'd be thinking the steels want to go side to side under the purlins or further back if your having a dormer.

 

[freddiemercurystwin]

There are a few other concerns:

The joist layout is irrelevant.
If the PWs are thin then why are they shown about 300 wide?
It’s not clear if the houses is detached, terraced or a semi.
Why is the loft floor insulated?
There’s no existing section – which means you can’t understand how the roof will be supported with the new structure.
Why are some bits a colour?
How do you access the storage areas?
The new dining room will need to be accessed from the hallway – you can’t have an escape route through a kitchen.
The insulation to the roof is not specified, neither is the insulation in the vertical walls.
Why is there insulation shown in the vertical loft dwarf walls and the pitched roof?
Structural design is completely lacking – but you know that bit – new floor thickness looks ambitious. Steel wall plates?
The bath in the loft ensuite looks like it won’t have adequate headroom to be practical.
If the section is accurate you’ll not achieve 2m over the new loft stairs.
Why is the bathroom door an FD?
If the ground floor stairs are not changing why is there a note mentioning 2m headroom above?
Normally you have a fat section at the top under the ridge to allow the insulation to be continuous.
Why is the glass in the rooflights laminated and toughened?
There’s no insulation shown on the party walls or gable walls – unless the neighbours have already converted their lofts and theses PW walls will effectively become internal?
There’s no mention of any background ventilation shown that I can see.

There are probably some others

 

[roganty]

A couple of thoughts on the layout from me.

How about switching the lower stairs around so they start in the lounge. If they are also moved further into the lounge, then upstairs they will end at the bathroom wall.

If you then box in the stairs you have created a protected route straight to the exit.

(Can someone correct me on this) Would the stairs need a door at the bottom, or could they be left open to the lounge?

You will then be able to create a more open plan kitchen/diner without needing to build walls and corridors.

*Edit:
Here's something I've just knocked up as an example

 

[^woody^]

It's even more important with loft conversions to accurately detail the floor, walls and roof/ceilings and then you can actually see if things are going to work out when its built. So no good drawing say a 150mm floor when it will need to be 250mm or 300mm or something because of the steel section size. Likewise for walls and any double joists and what not.

 

[rico_suave]

thanks for your inputs guys,

this is my first loft conversion design project as you can probably tell.

I have some pics of the existing loft structure. Can anyone shed some light on if a loft conversion will be viable with this current structure ?

I'm currently re-working the plans to with Woody's and Freddy's advice. Will post when complete

 

[freddiemercurystwin]

Looks like a pretty typical roof structure to me and two steels required, one beneath each lower purlin and a stud wall atop each one to support the purlin, new floor joists spanning between each steel. You need to employ your engineer now not later on and incorporate their design into yours.

 

[tony1851]

A couple of thoughts on the layout from me.

How about switching the lower stairs around so they start in the lounge. If they are also moved further into the lounge, then upstairs they will end at the bathroom wall.

If you then box in the stairs you have created a protected route straight to the exit.

(Can someone correct me on this) Would the stairs need a door at the bottom, or could they be left open to the lounge?

You will then be able to create a more open plan kitchen/diner without needing to build walls and corridors.

*Edit:
Here's something I've just knocked up as an example

View attachment 115449

Personally I think that layout would be a 'fail' because you've taken up nearly half the first floor with circulation space.
Ideally, you put the loft stairs over the existing stairs to save space.