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November 30, 2009

How do you adjust the floor-to-floor height of a kit spiral staircase?

A logical question that is worth knowing the answer to if you are contemplating using a spiral stair kit.

First some details of how spiral staircase kits are constructed.

The main structural element of a spiral stair is the centre pole. This pole usually made of metal tubing rises vertically through the centre point of the spiral staircase from top to bottom. This pole has a base plate at the bottom that secures it to the lower floor. The top of the pole terminates and is held in position at the upper floor level by the last tread which is usually a double sized triangular tread that acts as a landing platform.

This landing tread is attached to the centre pole in the middle of the spiral stair, and secured to the perimeter of the opening by brackets that fix under the tread to the vertical face of the trimming floor joists. These upper and lower centre pole fixings are the only structural fixing points that are necessary to secure spiral stair. Onto the pole are placed alternately metal or wood tubular sleeves and treads, the sleeves creating the required gaps between the treads. When completed the sleeves and treads will completely hide the structural centre pole from view.

OK so far so simple, but the problem is that floor-to-floor heights vary between buildings so that in practice you have to be able to vary the height of the centre pole sleeves to suit any specific overall height. The object of the exercise being to divide your total height (overall rise) by the number of required treads, which will give you a uniform gap between all treads ( the height between the top of one tread and the top of the next being called the tread rise)

The way that you vary the the height of the spiral stair centre pole sleeves can be tackled in a few ways. The perfect solution available only to more expensive made-to-measure spiral stairs is to predetermine the overall height, and cut the height of the sleeves to suit at the manufacturing stage.

Kit spiral stairs by their very nature need to be adjustable on site,so that they can be pre-boxed and ready to suit any floor-to-floor height, so other solutions are needed.

There are really two main solutions, both have disadvantages, but both solve the problem.

The most common solution by far, is to supply purpose made shims or washers that you introduce between sleeve and tread to adjust the tread rise. Typically the fitting instructions will supply a matrix table that will tell you the number of shims needed for any given overall height within the spiral staircase range. The disadvantage of this most common method is that you can only adjust the height to the accuracy of the thickness of a washer, although over the full height of the stair this unlikely to make a noticeable difference.

A rarer alternative is to have an adjustable sleeve that is usually adjustable using a screw mechanism. This will allow infinite adjustment of tread rise within the spiral stair height range, but has the disadvantage of looking more like a piece of farm machinery rather than an elegant centre pole to a spiral stair.

If you have been paying attention, you will have realised that not only do you have to be able to adjust the height of the tread rise, but you also need to be able to have a variable height to the centre pole. It is no good having a nice uniform tread rise and then having a fixed height centre pole sticking too high out of the top of the spiral stair.

This is done by making the centre pole fit the minimum design height of the spiral staircase, and then having a screw out threaded bar which in conjunction with bushes ( same outside diameter as the centre pole) allow the pole to extend up to the maximum spiral stair design height. As the centre pole is not visible when the stair is complete, its adjustment mechanism need only be functional not attractive.

The staircase doctor

November 24, 2009

Fitting tips for an SAF electric loft ladder

The installation of an SAF electric loft ladder is relatively straight forward as it is delivered to you in a complete preassembled and working unit. It will weigh approx 60Kg. and will be delivered to your kerb side on a pallet. The external dimensions will vary depending on which size you ordered, but typically it will be approx 750 wide 1050 long and 750 high. We recommend that at least two people carry it to its fitting location.

Whatever size of electric loft ladder that you order, for example 1000 x 700mm. that will also be the size of aperture that you will need to create in the ceiling. All fitting tolerances are allowed for in the frame during manufacture. Your aperture will need to be finished true and square to the exact dimensions. If the aperture is misshapen it will distort the electric loft ladder hatch frame, and that will in turn cause the hatch to jamb in the frame when you attempt to open it. The edges of the aperture should be formed on four sides with the same depth of joisting as the existing ceiling joists. There is no real need to put a facing on the vertical face or an architrave around the aperture, as most of the vertical face will be covered by the 125mm deep hatch frame. The 'L' shaped frame has a 30mm flange that acts as architrave to cover the cut edge of the plasterboard ceiling.

It is possible to install an SAF electric loft ladder on your own, but you will need a block and tackle. Set up the block and tackle in the loft on temporary shear legs or attach it to the rafters directly over the centre of the hatch. You then attach the hook to ropes that are fixed to the ladder frame at three points, so that it hangs horizontally when suspended. You go into the loft and pull the electric loft ladder up into the opening, first making sure that you have a power point and a cordless screwdriver with screws handy in the loft.

Once you have the ladder sitting in the opening you can fix it with the 4 top of joist clamps that are supplied with the kit. At this point you can remove the hook and add screw fixings through the predrilled holes in the side of the hatch frame. Make sure that you do not distort the frame when you are doing this, and pack at any screw point where there is a gap between timber joist and frame.You can then plug in the transformer input lead into a 13 amp socket outlet. This then allows you to press the switch and the electric loft ladder will descend freeing you from the loft.

The alternative method needs at least two more people but less equipment. As before arm yourself with the tools in the loft, then get at least two beefy colleagues to lift the ladder by hand into the opening. They will probably need a 'hop up' in order to reach the height required. While they hold it, you quickly fix as before described.

The SAF electric loft ladder is factory tested prior to delivery so it will work for you providing you have not distorted the frame during fixing. the main reason for non-operation is because the electrical system has blown a fuse due to motor overload through to many fast sequences of operation. We have learnt to include spare fuses and a fuse location photo in with the electric loft ladder because of the number of times we have encountered a phenomenon called 'playing about with it'. What happens is, you fit your electric loft ladder and are delighted as you send it up and down to test it.

Fair enough, no problem, but then you get the wife to show her. She gets the kids, and the kids think it is a computer game and play with trying to work out what score they have made. All the while the poor little motor is getting hotter and hotter until it blows a fuse. No big problem it requires the plug to be pulled out and the fuse changed as indicated in the fuse photo supplied. More spare fuses are available from electronic specialists like Maplins etc. Your will probably find that once the game is over it will not blow a fuse in years of use.

Two warnings.

  1. Only a suitably qualified electrical engineer should attempt to carry out any work on the electrical elements of an electric loft ladder.
  2. Young children (and some not so young but stupid) have a habit of thinking that an electrically operated loft ladder can also be used as an escalator. One stands on a tread while another presses the switch. Not a good idea!!

November 18, 2009

An electric loft ladder, is it what I really need?

Let us be honest, electrically operated loft ladders are a luxury item that you can live without. That said most of them are a joy to use, and for the less physically active or the regular loft user an electric loft ladder makes life so easy.Once you have taken the plunge and spent your hard earned cash you will not be able to imagine life without one. There is actually a third category of electric loft ladder buyer that I admit to being a member of, the bone idle gadget man, and yes it is always a man. Electric loft ladders can in some circumstances come under the banner of 'big toys for little boys'.

So as you are obviously not in the third category, lets look at the options now that you have already decided that you cannot wait for the next house party, when you can show your friends your new power access to the loft wine cellar.

There are a few variations on a theme, but basically electric loft ladders fall into two types, the wooden sliding or folding ladder and the metal concertina ladder (also known as a pantograph or scissor action). Both of these are invariably supplied complete with hatch and frame. The electric loft ladder operating mechanism needs to be secured to a purpose made frame, so they are not suitable as an add on to an existing hatchway.

Both types are also usually larger than a typical UK loft hatch size, usually a minimum of 1000mm.x 700mm. for the concertina type, and larger still for the wooden sliding type. Both types can be supplied with wall operating switches and or remote controls. Wall switches have the disadvantage that they need hard wiring to a wall. Remote switches have the disadvantages that they are easy to lose or break and are expensive to replace.

So which to choose? It is easier to give a list of advantages and disadvantages of both, then you can decide.

Wooden sliding or folding electrical loft ladders

Advantages

  • Can be made in various widths of ladder, and are capable of reaching up to very high ceiling heights.
  • Very solid with a nice wooden staircase feel.
  • Capable of manufacture with larger hatch sizes than the standard concertina models

Disadvantages

  • Far more expensive than the concertina electric loft ladder models, typically £ 3000 plus
  • Bulky and take up more room in the loft, particularly the sliding type which by their nature need to extend beyond the hatch when parked in the closed position. This can make them unsuitable for small or restricted loft areas.
  • Require larger more powerful motors to operate, these can be noisy.
  • Usually very slow to operate due to the heavier weight of the moving parts.

Metal concertina electrical loft ladders

Advantages

  • Cost less, typically £1800-£2500
  • Usually far faster to operate.
  • The concertina mechanism allows everything to fold up on top of the hatch, so they take up no extra loft space.
  • The lighter construction allows for smaller quieter motors.
  • The arms of the pantograph make perfectly placed secure hand grips ( most models of both types have handrails as well)
  • Generally quieter to operate.

Disadvantages

  • They are manufactured in standard sizes with fewer options for width and length of hatch.
  • Some pressed metal models can be a little noisy in operation, not a problem with aluminium models.
  • The metal treads can feel a little odd under foot unless carpeted ( carpets are standard are standard on some systems)

All in all I think that if your loft is a regularly used space in your house, then an electrical loft ladder will more than compensate for the initial outlay.

They are not only far more convenient to operate but also provide a far more comfortable access to the regular user.

Thus spake the lazy gadget freak

November 11, 2009

Advice on choosing your own stairs in a new build house or loft conversion

I regularly get requests from self-build house projects for alternative staircases to the stairs drawn on the original plans submitted by the architect.

A typical scenario is that the self builder employs an architect to draw up plans for submission to the Planning and Building Control departments. Unless told otherwise the architect will quite rightly plonk a house stair on the plans that he or she knows will comply with the Regs. This will invariably be a nice safe traditional timber design that will cause no problems. Approvals are obtained and everyone is happy so far.

As the building work progresses, the self-builder will quite rightly start to get involved in some of the finer details like colour schemes, kitchen fixtures etc. At this point someone usually realises one of two things

A, there is a really boring staircase proposed for the hallway, or

B, they have gone over budget and cannot afford the feature glass spiral staircase that seemed a good idea before the recession kicked in.

On the other hand if you are reading this blog because you are in the early design stage of a house build or refurbishment, well done you, that is the right time to look at such an important fitting as a stair in your dream home.

Staircases can and should be ordered and installed later in the building project, but the hole in the floor that the stair passes through has to be constructed early. The dimensions of this aperture are likely to be specific to the original stair design, and may need adapting if you are trying to change things. Altering trimming joists in an already constructed first or second floor can prove expensive.

If you are in the first category and are trying late in the day to change a staircase up market, do not panic yet. Assuming that the original design worked, the floor aperture size should also allow a similar but posher design to fit. This is likely to be a made-to-measue stair that by the nature of the beast can be made to suit. It may however be trickier if you are trying to save money and are going for say a stylish kit stair. These are made to a module and though they are invariably adaptable and can be squeezed in, the squeezing may put it outside of the all important Regs.

Probably the most common request that I get is from self-builders who half way through the building work realise that there is a whole loft area that they had not considered, and would now like to add onto the project as bedroom number 8 or 9.There is nothing wrong with this; it must be cheaper to do it during the main building work rather than later on. However again space for the access stair on the first floor has to be planned early. There nothing worse than realising too late that a very small alteration to your floor layout before it was built, would have allowed a lovely kit stair to access your extra bedroom.

The moral is think ahead, stairs take up space and need to be considered early in the project.

November 03, 2009

Modern trends in domestic staircases versus the Building Regulations

In the last twenty years there has been a major shift in domestic staircase design from functional to stylish. In my distant youth stairs were for going up and down on, not for looking at. Now staircases in new builds and conversions are out of the closet, they are works of art designed to show the owners taste and wealth. This is not a new phenomenon, the grand sweeping staircases of English manor houses of the past, were not about access, but about excess and the flaunting of wealth.

Personally, I like the modern trend, it is about time that such an important household fixture as a staircase caught up with its ostentatious cousins the fitted kitchen and the all singing and dancing power bathroom.

The only problem with this trend is the trend itself, which is leaning towards minimalist clean open lines in shiny stainless steel and glass. The stairs look beautiful, and in the ostentation stakes fit the bill superbly. The problem is the more minimalist the spiral staircase, the less likely it is to comply with the Building Regulations, which are about health and safety rather than grand designs.

In actual fact Grand Designs is probably the culprit, whether we like to admit it or not, most of us are heavily influenced by what we see on the telly. What we do see, are modern minimalist design staircases shown on the proliferation of home building or home make over programmes that have been in vogue for some time.

The main area of contention between minimalist stair design and the Regulations is the 100mm (4") sphere rule, which in a nutshell says that you cannot have a gap bigger than 100mm anywhere on a stair. This includes spiral stairs, spacesavers et al.

This together with the requiremnts for guarding of stairs ( balustrades), non-slip treads and non-climbable balustrading severely limits the degree of minimalisation that you can achieve. You will see on television, glass stair treads poking out from a wall with no other form of support or any form of balustrade. They look superb, but believe me you do not want to go there. Without serious modification, like balustrading and riser bars, such stairs will not pass muster with your inspector. Nor should they, I am all for style, but if you can fall off the side of a stair it is dangerous!

No one should be put off looking for a feature modern design staircase, they look superb and will totally change the entrance hall to your mansion. However be realistic from the start and seek advice before you set your heart on that stainless steel fireman's pole complete with leather landing pad that you saw on the telly.