renovating a beamed ceiling with wooden boarding

[davidinsussex]

good afternoon

my house is fully timbered and has some very nice, old , beamed ceilings which show the underneath of the floorboards from above between the beams.

unfortunately, while the floorboards are functional they are very shabby and i need to fill in the spaces between the beams. in our second floor bedroom the floorboards above are very shabby with holes etc, and while they are not load-bearing, looks a particular mess.

could anyone suggest please an elegant solution? I've thought about a thin layer of plasterboard fixed between the beams, but this would be extremely time-consuming and diffcult to fit accurately, and it's been suggested to me that I could have the underside of the boards plastered, which doesn't seem overly practical as surely this would fall off...

any suggestions gratefully received, thanks

 

[Moo]

Welcome to the forum, Dave. Your house sounds lovely!**

To start the ball rolling - there was a thread not that long ago about fitting stuff between ceiling beams. I can't remember much about it (except that it could be very difficult), but someone will be along shortly to point you in the right direction.
Another thought about your situation: while you're at it, what about putting some sort of sound insulation under the boards? I imagine that, as it is, you can hear every footfall on the floor above.


** Any chance of some photos?

 

[DaveBrigg]

Good evening and welcome. I tried the plasterboard route, and had just the problems you described. The uneven beams made it a nightmare to cut to the right shape, and it's not a material very forgiving of force. In the end I opted for hardboard. This will horrify many (I ripped out acres of the stuff before we moved in!) but it did the job. I was able to trim it slightly larger than the gap it so that it fits by pressure, and painted it with clay paints so that it matches the walls. It won't survive close scrutiny, but most importantly to me it is a fully reversible change, causing no damage to the original fabric. There are other materials which may be better, so wait and see what other advice is given.

What you do to the bedroom floorboards will depend on whether you are leaving them exposed, how much shabbiness you are willing to live with and most importantly, whether your house is listed.

 

[davidinsussex]

good morning folks and thanks for the replies.

interestingly, the stuff that I pulled down because it didn't pass close scrutiny was indeed hardboard!

I'm thinking that there must be a modern version of hardboard that gives some insulating and sound protection as well....to give the best of both worlds.

i'm not going to take out anything, with the really poor floorboards I'll overboard and underboard if necessary.

many thanks again

david

 

[christianb]

Hi David,

One practical solution to the problem of flexing (and thus cracking) of plaster on plasterboard is to fix it to battens a few mm below the floorboards rather than onto the boards themselves. A kind of "floating ceiling", I guess.

C.

 

[robgil]

if there are no signs of there ever being plaster on there then i would be tempted to leave well alone , if there was plaster on there then i can show you how mine are done , i shall get a photo later if you wish.
basically there are laths running in the same direction to the floor boards (over the rafters) then more laths are fixed to this running in the same direction as the rafters , daub has then been fixed to these laths. this ceiling has been here for many hundreds of years and only a small proportion of it has fallen down.
compared to the hard board used in other parts of the house it looks better by miles , this is how i will be replacing the hard board on my ceilings when i get round to it.

 

[Penners]

David - welcome to the forum.

Question number one - is the house listed? If so, then you'll need to have a word with your Conservation Officer to find out whether your plans require Listed Building Consent. I would start by just giving him/her a call for an informal chat about it. He/she may want to come and have a look. Obviously it would be advisable to emphasise that you want to insert this ceiling in order to avoid the necessity of replacing the old floorboards above.

Question two - is the ceiling structure suffering from any dampness?

If you're not listed, or if you are and the CO has no objection, and assuming there's no damp in the structure, here's the technique I would use. It does involve using plasterboard, but once you get the hang of it this needn't be the nightmare job that it appears to be.

First, fix counterbattens to the side faces of the flooring joists, making sure that each pair of battens is parallel. Leave enough joist below the bottom face of the battens to ensure that the joists will still protrude below the finished ceiling level. This leaves you with a "beamed" ceiling look. Now cut plasterboard to fit between the joists (see more notes on this below) and fit to the undersides of the battens. Skim with plaster. Lime plaster is more flexible than gypsum, so is the better choice, but I wouldn't get overly exercised about which you use from the breathability point-of-view. That's not really an issue with a dry suspended floor.

Here's a roughly cobbled-up sketch of the technique:



Getting the plasterboard an absolutely perfect fit between the joists isn't essential, but it needs to be a reasonably good fit if you're going to avoid a few hairline cracks in your plaster (although if some do appear, they are quite easily rectified with Polyfilla). But if your joists are a bit uneven, and meandre about a bit, here's how to cut the plasterboard to size.

1. Tie a taught stringline approximately up the centreline of the gap between two joists, to give you a datum. Try to get it as parallel as possible to at least one of the joists.

2. Working at regular intervals - say every 10cm - measure the distance from the stringline to the inside face of each joist. Note all these measurements down carefully.

3. Draw a pencil line down your plasterboard to represent the string. Now transfer your measurements on to the plasterboard, making pencil marks each side of this datum at the same intervals - in my example every 10cm. NB: Because you measured over your head, and you're marking out your plasterboard (presumably) on the floor, it's easy to get confused about which end is which. Just be careful about this.

4. Now use a ruler to join each pencil mark to its neighbours until you have a wiggly (note that technical expression!) line down each side of the datum.

5. Use a fine-toothed padsaw (a hacksaw blade is good) to cut carefully along your two wiggly lines, and across the ends. If you support the plasterboard well, you could use an electric jigsaw (with a hacksaw blade). Don't be tempted to use the normal Stanley knife cut-and-break technique to cut the plasterboard, because the constant changes of angle will cause the paper backing to separate from the plaster core.

You should end up with a plasterboard leaf that is pretty well tailored to the joist bay that you've been working on. Use dead men* to support it in place while you screw it to the battens.


* Tell me if you need an explanation of this expression.

 

[Moo]

a taught stringline

er - shouldn't that be 'taut'?

 

[robgil]

depending on the age of the house the joists could well be laid flat.

 

[FamilyWiggs]

Welcome to the forum David. It is customary to celebrate your first post by titliating the die-hards here with some porn (pics of your house)! :wink:

I can't add much to Penners' excellent post, save to say this is exactly what I did with my own non-parallel beams. I used "soundbloc" plasterboard which has enhanced sound-proofing qualities.

 

[robgil]

here are some pics , my joists are laid on their side so you can see how tight it is.

this is a section that has fallen away , probably because the floor boards above had been replaced at some point. you can see how close the laths are to the boards and how thick the daub is. for some reason i find myself really looking forward to repairing this damage, probably because i really like working with daub.

this part of the ceiling has been fixed with hardboard pressed into glass insulating and held in place by beading , and it looks like hardboard held in place by beading , there is no disguising this.

personally i would rather have exposed floorboards than anything other than plaster or daub but i am very fussy anyway. you could put plasterboard as tight as you can to the boards then lime plaster onto that , my neighbour has had that done and it looks fine.

 

[robgil]

forgot to add , ive seen exposed floorboards through joists that had been painted white , not ideal but didnt look terrible either , in fact they looked quite 'honest' to their surroundings if that makes any sense.

 

[davidinsussex]

thanks you all for your comments folks, greatly appreciated.

i'll have to find a pic of the house for you, but in essence it's a wealden hall with a later 18th century addition to the rear. the house has had very little done to it over years apart from covering over some of the beams with plasterboard and some of the fireplaces in the 1980's. all i'm doing is tidying up a little. i've done this twice before so i'm fairly experienced. found some fantastic details while i've been searching away!

 

[Penners]

a taught stringline

er - shouldn't that be 'taut'?

No, no, no - you thought I meant a stringline that's tight.

I meant one of the new "smart stringlines", which have a microchip embedded in them, and have been taught to run parallel with the beams.







Phew! I think I got away with it.

 

[inwood]

If you wish to scribe the shape of anything (in this case beam to plasterboard) this tool:
http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=9807032&ecamp=trf-005&CAWELAID=266914765
is invaluable.

It saves a lot of time on the datum and measurement method.

It does exactly what it says on the tin and living in an old house like we all do, it's a perfect piece of kit for all those wobbly walls. I use it all the time now.

You can probably find it cheaper elsewhere.

 

[Joiner]

Use an offcut from a piece of batten. Put a point on one end and drill a hole just big enough to take a pencil (soft lead) about an inch in from the point = one scribing tool for nil cost.

If the piece you're scribing is particularly irregular, drill a number of holes along the stick's length and choose the hole that is a distance from the point equal to the largest protruberance (on the wall/ceiling) plus a bit.

I always used to put a length of hardboard in the van and cut off a width wide enough to allow a good template to be marked against the wall/ceiling. You then mark the board to be scribed with a line = the width of the template, align the straight edge of the template with this line and trace the outline of the scribe along the edge of the board. Cut it and fix it.

 

[chuckey]

I can recommend Penners method. I had my plasterboard skimmed so the fit did not have to be "airtight". I used 16mm square battens screwed into the sides of the joists about 1/2" from the boards and split the glassfibre (4" thick as bought) into 1" thick bits. One point arising was a few joists which are twisted where they went in to the wall. I used a jig to get my level from the bottom of the joists, so at the wall end the new plastered surfaces are not truely horizontal. In retrospect I should have put up a string line along the wall and measured from this so the ends of the plastered sections all appear in line.
Frank

 

[yamin]

Looks like a lovely house from the teasing pics you've put up. Please find some of the whole house and post!

 

[robgil]

Looks like a lovely house from the teasing pics you've put up. Please find some of the whole house and post!

me or David?

 

[yamin]

Oh Robgil, I'm sorry, I mean yours! Got mixed us there!