Dining Room as Library...

[Edwardia]

Having decided to turn the dining room (currently DIY workshop) into a library, my first question is:

How do I find out how much weight the floor can take ? I wouldn't want to fill the walls with shelves, only to see my books subside gracefully into the foundations

Many thanks

 

[caliwag]

By Jove...that's an interesting one, but not one to answer remotely really. Workshop to library sort of implies a lack of even temperature as a result of insulation...what kind of space is it? Are you attaching shelves to the walls or are the shelves going to bear on the floor?
You can quite reasonably load the floors around the edges with every book you can find, because that's the area of least stress, but if you intend to assemble sets of shelves in the middle (rather like a library) then get a structural engineer in...that's advice for any library builders...paper is the heaviest thing you will store...! :roll:

 

[Andrew Bodenham]

As Caliwag rightly says, the most comprehensive answer to your question will arrive in an envelope just ahead of an invoice from a structural engineer. However, forumites may be able to give some general advice if you provide a bit more info about the construction details of your house and the kind of loads you want to apply to it.

 

[AMc]

How do I find out how much weight the floor can take ?

A definitive answer would come from a structural engineer who would want to inspect the floor and wall construction. Mine cost about £60 an hour and I would expect would be able to visit and do the calculations in that time if you've got access to the floor joists and wall. If you can measure the size and spacing of the joists and confirm they're in decent nick then you could probably do the maths yourself.

Assuming you have no noticeable 'spring' in the floor when you walk over it and brick/block walls I wouldn't be concerned myself HOWEVER you'd be mad to take the word of an internet chat room if you think there is cause for concern!


On the subject, if you're thinking of custom fitted shelves we used http://www.jali.co.uk to prefabricate units that exactly fitted our alcoves. They were designed using their software and were delivered flat packed in a couple of weeks. Reasonably easy to assemble and very sturdily constructed. They were MDF but we couldn't afford timber and a joiner and we wanted to paint them white anyway.

 

[Moo]

We had both walls of a long narrow room lined with bookcases floor to ceiling and, in our innocence, it didn't occur to us to worry about structural things. Twelve years on, the books have multiplied (as they tend to do) to such an extent that the shelves are now full to overflowing.
So far there's no sign of anything sinister happening to the house.

(The shelves rest on pegs in the floor-ceiling dividers, not on brackets fixed to the walls)

 

[chuckey]

Not much information here, how about what the age of the house is, what the floor construction is and what sort of condition the floor is in. I have a book case ~ 6' high, 3' wide and ~ 10" deep, totally full of books, no problem on a victorian floating floor.
My dad ran a corner shop, one day he noticed that the corner where the milk crates and the vertical deep freezer stood seemed to have a one inch gap between the skirting board and the floor . The joist ends underneath had rotted away so he propped the joists up with lumps of 4 X 2 on a paving stone (dampcourse !), lasted for more then 5 years.
Frank

 

[Edwardia]

Thank you for taking the time to reply The first time I tried to supply more info, the combination of Internet Explorer 8 and Vista flipped me back a page spontaneously and I lost the post So here goes..

It's the dining room of a 1905 terraced house with original floorboards and horsehair plaster. Used as a temporary DIY workshop because it has good light and not much furniture.

My mother purloined my trusty steel tape measure, but assuming I get it back, I will be able to measure thickness and width of both floorboards and joists under them (dining room is ground floor but floorboards are laid on joists about 6 inches above earth) and spacing between joists.

Height floor to ceiling is 8ft and I'm intending to have bookshelves floor to ceiling in traditional country house type style on as many walls as poss. I presume that the weight is spread between walls and floor therefore. I do know that some screws will have to go deeper into the wall than others as the plastering was done by hand and is not a uniform thickness, as would be the case with a plasterboard wall. In any case, I would want the shelving to be secured into brick not plaster.

The floor is level and dry without skirting board gaps. No spring either. The sitting room floorboards however have a gentle slope

 

[Andrew Bodenham]

Thanks for additional info. I'm assuming that you are talking about free-standing pieces of furniture rather than wall-channel-and -bracket type shelving.

Unless your floor turns out to be desperately under-designed I woudn't bother trying to get the walls involved in loadbearing. To achieve this you would need to establish a fixing system capable of withstanding high shear loads or generating sufficient friction at the fixings to resist the vertical load imposed by the bookshelves. This is very hard to achieve reliably where there is a layer of softish plaster involved, and you cannot be sure exactly which part of the brick you are fixing into. (Sod's Law states that you will end up in a mortar course...)

It can be done, of course, as anybody who has hung up kitchen cabinets will tell you, but it adds additional complication to the job.

If your joists are of reasonable depth (say 150mm +) then you should have no problems with bookcases along the wall where the joists run into the wall (or onto a good wall plate). The loading will be mainly shear, and the joists should be more than capable of resisting this. If you want to shelve along the walls which runs parallel to the joists then you need to have a more considered think. Depending on the joist spacing you could be concentrating all the load on one or two joists, in a bending configuration. This is the sort of situation where a bit of sag might be expected. A simple fix would be to lift a few boards for access and build up some little brick piers under the affected joists at say the mid-span and quarter-span points. Use something like a concrete paving slab bedded on mortar to spread the load into the underfloor soil, compacting it first if necessary. Wooden wedges or packing pieces will let you fine tune the heights. Then you can put the boards back, pop your bookcases on the floor and wheel in the encyclopedias an other weighty tomes safe in the knowledge that the floor is 'going nowhere'.

You mention taking the bookcases up the the ceiling. When customers ask me to design bookcases in this way I always try to persuade them to stop a good few inches short of the ceiling, for several reasons. Firstly, if you can see into corners of the ceiling it does make the room feel much bigger. Full height furniture can feel rather overbearing. Secondly the floor to ceiling height is unlikey to be constant across the room, so in places you'll be struggling to wedge the things in, and elsewhere wondering what to do with awkward gaps. Thirdly, having books 8' up might be good for archive storage, but they're not exactly accesible. Though perhaps you intend a ladder on rails, or a handsome set of library steps. Fourthly, unless you actually build the things in-situ it can be very hard to place heavy pieces of furniture when you have no little or no lifting allowance.

Depending on the front-to-back depth of the bookcases you may feel the need to bracket the tops to the wall for safety, particularly if you have any budding young mountaineers in the family.

Some food for thought I hope - though I'm sure you've thought through much of this already. By the way, how big is the room, i.e. what is the span of the joists?

 

[MdB]

If you can get some air gaps down the back of the bookshelf then that is good too.

 

[chuckey]

Andrew, I once put up some "spur" shelving, 6 uprights, 2" plugs and 42 screws into lime plaster. Once we loaded the shelves with my gentlemans magazines and my wife's which magazines, the whole thing started to peel of the wall . Had to replace all the fixings with 3" plugs and screws with every plug glued in place with filler (to repair hole in lime plaster). Its been good for 20 years since.
Frank

 

[Andrew Bodenham]

Yes, I like that Spur shelving system. Lots fixings to spread the load - if the screws can get a grip on something! Not very beautiful for a library though....

 

[Jon Maine]

This sort of loading on a floor will tend to overload joists with a shearing force, assuming that we are talking about the wall with the joist ends sitting in. With that in mind maybe its worth taking up the floorboard closest to the wall to check the condition of the joist ends, if they are sound no worries.

If you are talking about putting shelves along the length of the joists you need to worry more about the dimensions of the joists. Rule of thumb, jump up and down and if the floor feels very solid worry no further, if it has some bounce in it then you will need to check out the dimensions of the joists and get an opinion if you can give the span, height and width of the joists and the spacing along with the expected estimated weight and footprint of the bookshelf it may be possible to give an opinion on if it will be strong enough.

 

[Penners]

I know an easy way to tell if you have overloaded the floor...