A guide to the stages, what each stage involves and things to look out for.
This is a generic project template for cladding metal
I have added remarks occasionally, these are just things I have learnt to be aware of during these types of projects.
N.B. When possible and practical, it is far cheaper to have the staircase made entirely of wood, cladding a metal frame may cost three or four times the cost of the timber flight.
Below are a few images showing the staircase we will be looking at in this particular project,
The golden rule.
Check levels and dimensions of random rises and goings before starting.
I will go over this more farther down the page but whenever coming to a staircase substructure that has been fitted by a person or company that you have not worked with before this is very worthwhile doing before you do anything else.
Project overview.
Stair design.
When viewing one of our project pages, this will give you an idea The layout of the stairs for each project.
Project status: How far we are through the project.
A brief description of the project. the stage at which we have been instructed and the stages left to complete.
Project Stages.
Design intent.
The design concept for the stairs that the client would like to achieve.
e.g. Georgian with tread brackets, natural finish timber treads, painted risers, turned spindles and Mahogany handrail.
Components to consider at the design stage.
Nosing profile.
Tread thickness/material.
Riser thickness/material
Scotia molding.
Stringer transition.
Cut or closed string.
Stringer – soffit junction.
Stringer – riser junction.
Spindle type/size.
Handrail profile/material.
Any special design notes. e.g. Handrail heights raised at landing levels, handrail terminations.
Component design.
A design view showing each of the component parts, This is for the client. Dependant on the client a different amount of detail may be requiered.
With some clients you can work from generic visuals to get the design concept, others will like to see it as their stairs will be. In many cases working from the drawings is good enough for the visuals, other times it is of benefit to survey first and then work with the correct data to save drawing everything twice, this will also depend on the amount of detail that is created for the visuals.
Domestic house owners and designers may only want to see a visual representation of the staircase, while architects and joinery shops etc. are more likely even at this stage wanting to see how the component parts connect.
It is however worth doing a few checks early on to confirm that the stairs are level both along the flight and left to right.
When creating just a design visual, not so important.
When drawing a more detailed visual with technical details it is best to check the stairs first, I have surveyed stairs to find that the rises have varied by up to 16mm – 5/8″. and the treads themselve out by as much as 9mm 3/8″ and that is across just one tread. This amount of variation is not going to be lost in the cladding unless a large tolerance has been left for the cladding.
Check out the drawing section for drawing the component parts.
Survey of sub structure.
With the design in place, the survey data can be collected, if not already obtained, dependant on programme timing etc. The survey data is not genrally required until this stage, this allows for the design to be confirmed before spending time surveying.
I now use digital equipment for surveying many of my projects, I will still take physical measurments and confirm levels the old fashioned way, well not that old, I have moved on from water levels to spirit levels!
This will allow you to confirm any suspicions that you may have when you return to the office and start working with the digital data. Especially when the job is a long way from home.
I have found it useful to find a corner of the hallway and draw with a spirit level or laser level vertical lines on two adjacent walls, with a horizontal line across the corner. This makes it very easy to align the construction planes. Many of the properties on which I work are over a hundred years old, with bomb damage to the foundations or set on a clay base, which can move and tilt. Not all buildings have level floors, even new build.
Physical measurements.
These are a few of the points that I will check manually for each flight.
Digital scanning equipment is getting better but I still like to have a few measurements I have taken as I would if carrying out a survey without the use of a computer.
The main points for each flight will be
Riser 1 height: Left and right.
Going 2 distance: Left and right. Spirit level across the width and with the going.
Riser 2 height: Left and right.
Mid flight riser height: Left and right.
Mid flight going: Left and right. Spirit level across the width and with the going.
Penultimate riser height: Left and right.
stLast going before landing: distance left and right. Spirit level across the width and with the going.
Last riser height: left and right.
These are the main points that will show any adjustment that you may have for acheiving the ffl required. If the finished floors are already down then you can use this to check that the first and last riser heights will be equal, once covered. These measurements are worth taking when fitting to someone else’s sub structure.
Check list, before drawing the cladding system.
I have listed up some of the details that will need to be checked, I have added options that to the purist should not even exist but in this modern day of jobs being carried out in unusual ways, I have included them to show how to overcome design flaws, created in the earlier stages of a project.
Design details.
Intent.
An idea of the clients expectations.
With detailed section drawings signed off.
Stringer style.
Riser/stringer junction.
Mitred.
face mounted with shadow gap
Treads
Nosing projection.
Nosing profile.
Scotia molding.
Return nosing.
Profiled end.
Stringer/plaster soffit
finishing at same level.
plastered into bead.
Shadow gap between.
Inset soffit – distance inset by.
Design to bottom of stringer for inset soffit.
SFL/FFL
Distance from structural floor level to sub structure top of first tread.
Distance from finished floor level to sub structure top of first tread.
Distance from top of last sub structure going to structural floor level.
Distance from top of last sub structure going to finished floor level.
Check any structure being clad.
Using spirit levels, plumb lines, tape measures and any other device you may have at hand, carry out a quick check to see if treads and risers are level and vertical.
Edges of different flights that are meant to sit over each other, do so.
Parallel flights, are so.
Stair structure thickness.
Confirm from tread surface the amount of structure set under the stairs, both on any landing spaces and through the pitches.
Required to know where to set the bottom of the stringer, especially through drums.
Floor thickness.
The distance between ffl and skim coat to the ceiling beneath.
Required to know where to set the bottom of the stringer.
Working drawings.
This is where we draw each of the components tread by tread riser by riser etc. and ensure they all work together.
Once you have the survey data and design intent the nitty gritty bit starts, Producing the working drawings.
This is the technical stage where you have to draw all the components, often produced by different manufacturers, these parts must work together when delivered to site, with the possibility that there will be another company involved in the installation stage.
This is the responsability stage, any design fualt or lack of design may cost many man hours or even worse mean having to manufacture parts again. when designing the component parts if you can not see how it will work on the drawings, chances are it will not work on site.
When working with modern day cad programmes as so many do, it is very easy to check the parts connect correctly. A good understanding of how the fitting is carried out and how much clearance is required for fitting the parts is very usefull. When not sure it is worth while running it past any trades involved to confirm they are happy with the parts drawn and how they assemble, before you go into production.
Having had an engineering education before I turned to carpentry, cladding steel with wood still concerns me, temprature works in different ways with each product.
Heat will expand metal and contract wood. Even at a constant temprature I have found wood is likely to move, mainly in its first year fitted.
Production.
Once all the parts have been drawn it is time to issue them to the various manufacturers, or produce them in house.
With correct design this should be plain sailing from here on.
Summary.
The notes above are the basic notes I use when working on this style of project, I may update these if I find more information that I believe will help carry out the project with less time wasted or more accuracy.
The best way.
These staircases should be designed from handrail down, by getting the handrail flow to work correctly and then drawing down through the spindles, from here you can determine the stringer faces, riser positions etc.
Then once this has been achieved the steel framework can be designed with the appropriate amount of clearance for everything to work around it.