Broad window boards - single piece of oak?

[mbga9pgf]

Hi all,

very quick question, I am about to order a load of window boards in 22mm planed all round 1st quality Oak. ALL of the sawmills and timber places I have spoke to have reassured me I wont have to rip them up and biccy joint to prevent warpage. Some of the boards are 260mm wide, I am concerned I am going to get a load of window boards curling up in 6 months once it gets humid again.

If I seal the bases with multicoats of sealer and use decent fixings, will I have a problem you think?

I know I really should rip em up and biscuit join, but I dont have many joinery tools and am on a bit of a budget.

What you reckon?

Thanks in advance!

 

[Deleted member 174758]

Seal them properly and fix down with two rows of counterbored screws (pelleted) and Grip Fill (the board) in place. Should be OK

 

[ladylola]

I must admit to not being a big fan of pellets. They need really to be cut out from the underside of the boards to obtain anything like a decent match and to me at least they still stand out unless done very carefully.
If it's an old building then I'd say fix with cut nails , looks so much more original. If it's a newish building you could always screw a ply board down first and then the oak on top either fixing with pins or even just glue.

 

[Deleted member 174758]

If it's an old building then I'd say fix with cut nails , looks so much more original. If it's a newish building you could always screw a ply board down first and then the oak on top either fixing with pins or even just glue.

Well, I've worked on a few oak panelled refurbs in recent years (offices and pubs) and I've yet to see oak window boards nailed into place. Granted the last three were all post 1850 (the newest was 1931), but in each case everything (panels, window boards, skirtings, etc) was screwed and pelleted. Oak window boards with iron nails is a sure fire way to get black marks over time; moisture + tannin in the oak = tannic acid; tannic acid + steel or iron = ferric oxide (or inedilible black stains). In this part of the world window boards tend to get damp in winter because of condensation so you would never see them nailed

 

[ladylola]

I agree that it's fallen out of practice but I've seen , and fixed , boards into place with nails. As I said it's a personal thing that I'm not fond of pellets, to me they are all too often neither one thing or the other, they don't fully hide the fixing and they don't go down the route of making it a feature. As to the staining yes you are correct this may very well occur but again in this case it wouldn't bother me although I'm probably in the minority there.
mdga9pgf - you will be fine with J&K's method, just thought I'd stick my twopence worth in.

 

[mbga9pgf]

I agree that it's fallen out of practice but I've seen , and fixed , boards into place with nails. As I said it's a personal thing that I'm not fond of pellets, to me they are all too often neither one thing or the other, they don't fully hide the fixing and they don't go down the route of making it a feature. As to the staining yes you are correct this may very well occur but again in this case it wouldn't bother me although I'm probably in the minority there.
mdga9pgf - you will be fine with J&K's method, just thought I'd stick my twopence worth in.

Thank you all! Just need to find a decent router, table and pellet cutter and hopefully I can get the 20 sills installed in a week! Unfortunately, due to the age of the prop, I am going to have to cut each one to shape individually, no straight walls, some are deeper at one side than the other.

Was really worried about the warpage, but if you reckon 2 rows of fixings will do it, I will give it a try. Just need to grab a few boxes of gripfil

Have heard some use expanding foam as an additional adhesive to fixings, is this gash or is it an accepted method of securing boards?

 

[Deleted member 174758]

Just need to find a decent router, table and pellet cutter and hopefully I can get the 20 sills installed in a week!

Why a router table? A round-over bearing cutter will do one side and the other side can be handled with the fence in place - just do the notches with a hand saw/jig saw after rounding-over. For plug cutters Axminster are pretty good although personally I'd just go for a Trend 1/2in #10 set

Unfortunately, due to the age of the prop, I am going to have to cut each one to shape individually, no straight walls, some are deeper at one side than the other.

That happens even on new properties in my experience.

Was really worried about the warpage, but if you reckon 2 rows of fixings will do it, I will give it a try. Just need to grab a few boxes of gripfil

Have heard some use expanding foam as an additional adhesive to fixings, is this gash or is it an accepted method of securing boards?

I'd avoid using expanding foam - the clue is in the name. It expands and therefore can bow or warp the timber quite badly unless you go overboard with fixings. If the amount of space beneath the window boards is huge you might be as well raising it somewhat with "compo" (mortar) to just below the level you need - that's cheaper than GripFill. Either way you'l still require packers (ideally just below each screw hole so that you fix through them). I would also make sure that you seal/treat the undersides and rear/side edges of the boards before fixing in place - anything waterproof will do - final finish to old gloss paint if you are running tight on materials.

For a better look and increased durability I'd also caulk round the visible joints between the wall/window frame and the windowboards with matching coloured silicone. If you're uncertain about how to do this neatly get yourself a set of silicone "fingers" - they're sold as Fugenboy or Fugi sets

 

[ladylola]

You can use expanding foam but it's best to take J&K 's advice and avoid it. I've used it as a glue in a couple of instances but it is difficult to use and requires measures to prevent the timber being forced out of shape.
I've also got to echo J&K's experience of window boards in new buildings, best to measure and cut individualy

 

[northernstair]

Im not saying use expanding foam in this situation but I used to swear by it when gluing winder treads or staircase strings together, the glue dries stronger than the timber but as above you must be careful with the fixings and use very little (because it obviously expands!) To be completely honest if I was changing my window boards I would use 22mm oak faced MDF with a solid oak bullnose, no warping (if kept flat before installation!)

 

[northernstair]

I meant expanding glue, polyurethane! not the foam! I thought that was used in door and window installation sorry about that!

 

[Deleted member 174758]

To be completely honest if I was changing my window boards I would use 22mm oak faced MDF with a solid oak bullnose, no warping (if kept flat before installation!)

I wouldn't. In the last year I've ripped out two sets of veneered MDF window boards which got wet and were shot - a combination of condensation from the windows and spillages (pub/restaurants - so a lot of windows, a lot of spillages). On my current job we'll be ripping out another set which went in when the building was put up in the late 90s (so around 15 years or so old). Don't get me wrong I like MDF for skirts and architraves where it is a lot easier to install and get a good painted finish on than softwood, but window boards are subjected to a lot more abuse and need to be fully protected with two coats of primer and the same of top coat (OK for plain MR-MDF boards providing the paintwork is maintained) - not a single wipe over with some Ronseal lacquer where it shows.

I meant expanding glue, polyurethane! not the foam! I thought that was used in door and window installation?

It is used in windows, but often only after they've been glazed (otherwise you might find that you couldn't get the glass/DG units in). On door casings it needs to be used very sparingly to avoid bowing out the jambs. I've seen cowboys go at it with the foam gun only to find they couldn't hang the door afterwards - or in other cases couldn't get the door open! (Made that mistake myself ). Pity is in the UK we rarely see the low expansion foam they use in the USA and elsewhere