| Author | Message | ||
     Marcoattici (Marcoattici) Intermediate Member Username: Marcoattici Post Number: 35 Registered: 06-2012 |
we are kind of closing the valley using this alluminium bracket (hand crafted) should it be good enought? any suggestion on how to do when the inverted v valley is reaching the main ridge? thanks   | ||
| Marcoattici (Marcoattici) Intermediate Member Username: Marcoattici Post Number: 34 Registered: 06-2012 |
thanks Old_school in the end we decided for the ss hook as you can see   | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 974 Registered: 01-2009 |
Being that close to the ridge, I am sure nothing will pull them free. The reason they don't use clips like that to fix "repaired" slates is that they snow will slide down the roof and bend them over and pull out the slates. Looking back at the pictures you posted I see that the straps will go right over the ridge and hold on both sides. Certainly an interesting way to do it. It should be fine. good luck with that. | ||
| Marcoattici (Marcoattici) Intermediate Member Username: Marcoattici Post Number: 33 Registered: 06-2012 |
here we are again after the winter stop with some pictures of the roof, finally progressing. getting close to the ridge we wanted to place some tiles horizontally held by a hook like in the drawing of some times ago. using a piece of 0.9mm alluminium (the same used for the valley flashing) curved like a hook. the question is: will it be strong enough and how long will it last? any of you have experience of this kind? thanks   | ||
| Catfeesh (Catfeesh) Intermediate Member Username: Catfeesh Post Number: 38 Registered: 12-2011 |
I believe the hole position has to be taken into account. Unless you have adequate sidelap (3") with the slate above, it will reduce your effective headlap. That rule shouldn't hold up in all instances eg. long slates with minimal headlap. | ||
| Marcoattici (Marcoattici) Intermediate Member Username: Marcoattici Post Number: 32 Registered: 06-2012 |
just a doubt. when we speak about headlap is the position of the hole taken into account? i mean if our screw hole is placed 2 inches from the top of the slates and we want 4 inches headlap, will the headlap's line be 6 inches from the top line? | ||
| Marcoattici (Marcoattici) Intermediate Member Username: Marcoattici Post Number: 31 Registered: 06-2012 |
Blue sky roofing, i see. the ridge slates were meant to be placed like this: the first line with two screws at 1 1/2" from the edge, the second line placed with half slate overlap 12", the third line again 12" overlap on the second which means that is in line with the first. we were also going to do kind of 'drip lip' making a slight cut on the slates 1/2" from the edge but it can weaking the stone this 'pry bar' wind effect makes sense | ||
| Blue_sky_roofing (Blue_sky_roofing) Senior Member Username: Blue_sky_roofing Post Number: 56 Registered: 05-2010 |
How exactly are you doing this ridge? I assume you would be 'interlocking' the slate: meaning that you would begin with a 24" on the bottom, 16" for the middle, and then 8" on the top to start the staggered process. Or were you planning on just taking 3 12x24's stacked together with the metal cleat covering the seams every 24"? Here is an idea for you: Why not reverse the process? Reverse your cleat: Put your cleat on first (upside down from your drawing) on the ridge board using at least 2 screws across the board (cleat in essence would be 12" wide underneath the slate, coming up the thickness of 3 slate, and then 1" or so on top of each side of slate) Slide 24" slate in the cleat, then a 12x16, then a 12x8 for the top. Continue on down the ridge then with 24". Have the cleats positioned were it would hold the seam of the top row. In this design, the slate would be up off the ridge board (flashing) the thickness of the cleat; but see 'Option #1'. (I realize that the top row slate seams would be left exposed inbetween the '1" return' of the cleat, but water would still make it to the seam in your drawing, working its way underneath the cleat to the seam) Option #1: You could put liquid nails on each outside edge of ridge board (or the flashing as per your picture) with the bead higher than the thickness of the cleat, before you put the first row of slate down for additional holding power against wind (I'll say it again: the wind is going to act like a 'pry bar' in this design, and a screw through 1 thickness of slate doesn't seem adaquate to me). Option #2: Before you install the 1st 12x 24 slate, put a bead of caulking on the underside of slate back about a 1/2" or so from the outside edge of each side, to act as a 'drip lip' for water coming off the top row of slate (otherwise, water may want to wick all the way back to the ridge board on the underside of 1st row of slate. | ||
| Marcoattici (Marcoattici) Member Username: Marcoattici Post Number: 29 Registered: 06-2012 |
old_school yes it's true we have maximum 2 or 3 days of snow in a row at time. and usually 2 or 3 times in a year. the temperature in the worst condition are between -3 morning and + 4 midday so the snow doesn't last more then 2 or 3 days usually blu sky roofing, that was also our thought. The screws and the water capillary effect. Would you put some caulk on the screws? Or would you suggest any other kind of solution? For the wind the stones seem to be fine, 3 layers of 12 x 24 inches slates are quite heavy.  | ||
| Blue_sky_roofing (Blue_sky_roofing) Senior Member Username: Blue_sky_roofing Post Number: 55 Registered: 05-2010 |
I'd be concerned with how wind might want to 'remove' the 3 layers of slate stacked horizontally on the ridge. There is also going to be a ton of capillary action between those slate - water possibly reaching the screw on the 1st row of slate. | ||
| Chris (Chris) Senior Member Username: Chris Post Number: 170 Registered: 09-2009 |
ah, the falling water inspired ridgecap design | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 929 Registered: 01-2009 |
That is certainly an interesting way to install a ridge. Never seen it done like that, but then again, if it doesn't leak, you are golden. Obviously you don't have any snow or ice there? | ||
| Marcoattici (Marcoattici) Member Username: Marcoattici Post Number: 28 Registered: 06-2012 |
ok thanks old_school. here below there is a scheme of the ridge we would put up. what do you think? there is a screw passing trough the first orizontal slate which is also passing trough the aluminium flashing.  | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 928 Registered: 01-2009 |
Before you install them, tap them with your hammer to see if they "ring" A cracked slate will have a hollow "thud" and you know to throw it away. | ||
| Marcoattici (Marcoattici) Member Username: Marcoattici Post Number: 27 Registered: 06-2012 |
ok Joe we'll do that. it will take little more time to get there just because we are facing an unexpected problem at the moment. we had just finished the veranda part of the deck when, trying it with water, we discovered quite a number of slates which were showing one or more lines of water remaining on the stone itself. we removed them and we discovered that some of the slates had a hardly visible line of crack, corrispondent on both sides. Some of them have lines only on one side. should we remove those also? have you ever faced this kind of problem? how do you check your slates?? | ||
| Joe (Joe) Moderator Username: Joe Post Number: 751 Registered: 07-2006 |
You are showing 3 layers of stone where there should be only two. Just hold the stone back from the V groove a little. | ||
| Marcoattici (Marcoattici) Member Username: Marcoattici Post Number: 26 Registered: 06-2012 |
yes joe u are right it was not a precise sketch. the question was about the inverted V flashing position: shall we have it a little far from the center of the valley just to allow the stone from the higher pitch not to overcome it?  | ||
| Joe (Joe) Moderator Username: Joe Post Number: 750 Registered: 07-2006 |
A valley is the joint between two sloped roof planes. You are showing a dormer on one side, so I don't know that I fully understand your situation.  | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 927 Registered: 01-2009 |
On the low slope side of the valley, you may want to bend a hem in the metal, and you don't have to smash it all the way down. That way if any water gets back that far, the hem will direct the water back down on the metal and eventually off the roof. | ||
| Marcoattici (Marcoattici) Member Username: Marcoattici Post Number: 25 Registered: 06-2012 |
Joe: we are going to do the inverted V flashing as per your suggestion.. we were thinking to do as per the sketch here below so that the dormer's slates have enought space to let the water flowing. we are trying to close as much as we can do the valley even leaving 7 inches minimum on the dormers and 11 on the deck before the nailing. will it be ok? there is also a scheme of how we are going to move from the veranda to the house's deck. what do you think about?   | ||
| Joe (Joe) Moderator Username: Joe Post Number: 748 Registered: 07-2006 |
When flashing between asymetrical slopes, an "inverted V groove" is formed into the valley to prevent sideways flow of water from the steep slope into the lower slope. You can run one continuous piece of valley flashing with the inverted V groove and just slate up to the V, being careful not to nail anywhere in the valley except on the outermost edges. The valley metal typically extends underneath the slates 5", but I would extend it further underneath any low slopes (i.e. 4:12 to 6:12). Allow 2" for the groove, 5" under the steep slope, and maybe 11" under the low slope, requiring an 18" piece of metal. If your metal is wider, run the flashing further under the slates on either side. | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 924 Registered: 01-2009 |
Marcoatttici, since it is on the ridge, even some plastic cement with some slate dust over it would work. It is a shed point. As to the variance in the pitch of the two side, I say again, look at how they did them on your sample building and so if it is leaking. If not, I am sure you can duplicate that with no problems. If you put the valleys together like I mentioned with the longer portion of the aluminum flashing on the flatter pitch and also keeping them on the high side of the slates, there will be two layers of aluminum flashing before the cut is exposed. The water will have to flow up 16 inches and sideways at least 12 inches to get through to the inside. the difference in the pitches will make it challenging, for sure, and you will have to "skip" a course now and then on the steep side. It will be ok. Don't slow down, "Charge" | ||
| Marcoattici (Marcoattici) Member Username: Marcoattici Post Number: 24 Registered: 06-2012 |
old: the caulk was meant to be for some screws on the ridge flashing that we are still studying at the moment. we are getting to a couple of solution but nothing fixed yet. we'll let you know. i'll send you some sketch in the next few days joe: i see. our valley it's a strange one. it comes between a deck of 4:12 of a pitch and a dormier of 10:12 of a pitch. not much of a simmetry as u can easly image. as per you bible we got about .04 aluminium rool to oragnize the valley. which tickness would you suggested us in case of steinless steel valley, since here copper it's too expensive | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 923 Registered: 01-2009 |
Stuart, I agree with you on that one, but silicone is better than tar. We have been using a Conklin caulk for the last few months that is Urethane based and I am very impressed with it. Expensive, but very strong and like a weld for sure. 1,000% flexible too, with a memory so it comes back. Very strong and very good. | ||
| Lazeyjack (Lazeyjack) Senior Member Username: Lazeyjack Post Number: 74 Registered: 04-2012 |
Did I see mention of Silicon sealer? For what it is worth, we never use it , in the marine or building industry Using urethane sealers only which will hold in high rise windows and also sometimes is used instead of welds!! in small boat structureSilocon fails and quickly too, little adhesion, will not hold paint best rgds Stuart | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 920 Registered: 01-2009 |
Joe, the reason I said 30 x 18 was that they sounded like they were going to use a type of "builders roll" and that comes in 18" widths. I would like to see a bit more coverage on the 3.5 / 12 side too, and that was my thought on having a bit more on the flat side. they were not going to use copper was my understanding. | ||
| Joe (Joe) Moderator Username: Joe Post Number: 746 Registered: 07-2006 |
We typically use 16" X 16" copper squares in closed valleys with the points of two corners aligned with the valley as shown in the Slate Roof Bible, 2nd edition, page 271. | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 919 Registered: 01-2009 |
Most all of them are "Lifetime", but they don't tell you whose lifetime they are talking about. If it is going to be covered, it will last as the sun can't get to it. What are you going to caulk? | ||
| Marcoattici (Marcoattici) Member Username: Marcoattici Post Number: 23 Registered: 06-2012 |
ok Old thanks we'll try it. in the bible is mentioned the lifetime silicone caulk, which brand would u suggest if any? | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 916 Registered: 01-2009 |
If I am understanding you correctly, all you have to do is cut some pieces of metal (Aluminum or steel or copper, about 24 inches wide and install them in the valley as you progress up the valley, doing both sides as you go up. I can see the dormers you are talking about on the first post, and you should be able to look and see how they are done and follow along. I would make the pieces of metal about 24 inches by 30 and put 12 inches on the step side and the other 18 on the low sloped side. Go across the TOP of the slates, about one third of the way down the slate so that the next two courses of slate covers it up. You don't have to butt the slates tightly together in the valley either. give it a half an inch gap or so, but keep them straight. Doing it this way, you will have a full double co9verage of metal in the valley too. good luck. | ||
| Marcoattici (Marcoattici) Member Username: Marcoattici Post Number: 22 Registered: 06-2012 |
yes scottish, mostly for ventilation, since we don't have much insulation underneath, and this case it' a typical local design that we are following. the gap it's only 1 inch anyway, Old, and sidelap it's 5,5inches either side. max of 8 inches expose for a 24 inches slates it' a lot of headlap. we should be fine.. we were asking to Joe a question that i think you also must know about the step valley flashing, we were reading the bible and we are not clear at the moment. can you tell us how to go about it having slate 12x24 like the pic. which should be the size of the step valley and so on. having a big different of incline between deck and gable the first it's about 5-12 the second 11-12 we would like to have a covered valley but we don't know how | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 157 Registered: 01-2012 |
It vents the roof old school we do it sometimes here on barns where animals are housed | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 913 Registered: 01-2009 |
Why the large spacing between the slates? One would think that with the combination of the flatter pitch and the large gaps it would leak from wind blown water. | ||
| Marcoattici (Marcoattici) Member Username: Marcoattici Post Number: 21 Registered: 06-2012 |
I see Joe. look at these stones we are putting up now.. they are coming from Himachal what do you think about? the brown color on the stones it's just mud. Joe we are trying to follow the bible about the step valley flashing, and we are not clear at the moment. can you tell us how to go about it having slate 12x24 like the pic. which should be the size of the step valley and so on.     | ||
| Joe (Joe) Moderator Username: Joe Post Number: 745 Registered: 07-2006 |
The photo of the weathered slate doesn't look the same as the photos of the other slates. I have seen lots of the weathered Indian slates because it's used for flooring and I have laid a lot of it at my own place (on walls and floors). It is not suitable for roofing, nor for outdoor applications. The rust will leach out and stain the surroundings. Someone sent me a photo recently of the Indian slate used as outdoor cladding. It was running rust stains onto the floor. On the other hand, some pretty good roofing slates come out of India. But the rusty ones shouldn't be used for roofing. | ||
| Marcoattici (Marcoattici) Junior Member Username: Marcoattici Post Number: 20 Registered: 06-2012 |
Joe: strange you don't reconize the stones we got from the place mentioned on your bible. under India Himachal stones Old-mohawk: it's true these are exactly himachal pradesh slates :D. just to be a little more specific Old-mohawk if our valley it's an aluminium one, and in this market, we have only stainless steel fasteners available or aluminium rivets, which one would you use? | ||
| Olde_mohawk_masonry__historic_restoration (Olde_mohawk_masonry__historic_restoration) Senior Member Username: Olde_mohawk_masonry__historic_restoration Post Number: 180 Registered: 04-2007 |
Weathered Himachal slate  | ||
| Olde_mohawk_masonry__historic_restoration (Olde_mohawk_masonry__historic_restoration) Senior Member Username: Olde_mohawk_masonry__historic_restoration Post Number: 179 Registered: 04-2007 |
The slate is from the Himachal Pradesh region in India. The rust spots are iron (Fe2O3) deposits within the slate bleeding out. Oxides of iron can make up as much as 8% of its composition. The metal selected for fasteners and flashings must be compatible with iron or a galvanic reaction will occur and they will fail. | ||
| Joe (Joe) Moderator Username: Joe Post Number: 744 Registered: 07-2006 |
I don't recognize the type of slate. We typically attach valleys to the deck with nails. | ||
| Marcoattici (Marcoattici) Junior Member Username: Marcoattici Post Number: 19 Registered: 06-2012 |
shall we use stainless steel screws to fix the valley on the deck since aluminium ones are not available here in the market or shall we go for aluminium rivets? | ||
| Marcoattici (Marcoattici) Junior Member Username: Marcoattici Post Number: 18 Registered: 06-2012 |
Hi Joe, here is the front side of the rusting slate. what do you think?? At the moment we are starting the roof again with these new himachal's slates and of course many questions are rising up. Reading your bible we discovered you to use 1mm thick aluminium valley sheet. here, on site, we have around 0.6mm thick alluminium roll. Do you think we have to put it double layer?  | ||
| Joe (Joe) Moderator Username: Joe Post Number: 736 Registered: 07-2006 |
Marcoattici - let's see the front of the slate, not the back. | ||
| Marcoattici (Marcoattici) Junior Member Username: Marcoattici Post Number: 17 Registered: 06-2012 |
have a look of this slate, we have only few of them, they seem to be kind of rusty.. what do you think?? shall we avoid to put them on the roof??   | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 147 Registered: 01-2012 |
if not using breathable felt i would put a continuous vent in the eaves i would also leave a 25mm gap along either side of the center of the ridge this would provide you with air flow on looking at your drawing i believe your using the hooks at the eaves because of the size of your over hang and if its windy condition's cheek nail every third course it will hold the next two courses below in place | ||
| Marcoattici (Marcoattici) Junior Member Username: Marcoattici Post Number: 15 Registered: 06-2012 |
thanks Scottish. what about if our underlayment it's not breathable?? what would you suggest us then? would it cause condensation phenomena? and have you ever used hooks like we are doing to avoid the lifting of the first course of slates in strong wind condition?? thanks | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 146 Registered: 01-2012 |
If using breathable felt all the laps are usually taped and where the felt meets the gutter the breathable felt is normal cut a few inchs above the gutter and you add in a felt called 5u the breathable felt will rot and flap in the wind if you take it down into the gutter | ||
| Marcoattici (Marcoattici) Junior Member Username: Marcoattici Post Number: 14 Registered: 06-2012 |
just two question. how can condensation be avoided between underlayment veltisun of monier company (does any of you know it?) and the deck. we have strong and, at times, very strong wind conditions here. as per the pictures posted we are using hooks to hold the first line of slates which is extending 5 inches past the edge. how much should these stainless steel hooks be thick? 2, 3 millimiter or more having them placed one for each slate thanks  | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 139 Registered: 01-2012 |
without counter battens | ||
| Marcoattici (Marcoattici) Junior Member Username: Marcoattici Post Number: 13 Registered: 06-2012 |
do you mean without underlayment or without the counter-battens? | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 138 Registered: 01-2012 |
it will breathe through the slates without that | ||
| Marcoattici (Marcoattici) Junior Member Username: Marcoattici Post Number: 12 Registered: 06-2012 |
thanks. do you guys think that an underlayment (such the veltisun of monier company) could be dangerous if placed on top of the deck just under the slates? i mean to avoid moisture problems. do you think that would be better to place the underlayment on the deck and the slates on a counter-battens system like old_school was suggesting, to allow an air flowing passage? | ||
| Lazeyjack (Lazeyjack) Senior Member Username: Lazeyjack Post Number: 67 Registered: 04-2012 |
abt decks In the past I have posted about ply and how ply can be wonderful if treated or painted BUT I have neglected to think abt moisture penetrating the ply around the nails So it would seem to me that the timber(or ply) would either need to be some medium that does not rot , with ingress of fresh water?I knew of no timber other than the hardwoods of the Pacific or the Teak, oak hates water OR if say, there are no leaks, then does humidity not become a problem, I must admit I am somewhat confused Scotty has some pics of OLD oak decks, like real old, not bad shape, and he and his team have just reslated Why should I care, be dead long before it rots, but then , how can one not build forever? best rgds Stuart | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 855 Registered: 01-2009 |
No, and the width of the slates will tend to span that too. Very few of them will be right in the middle of the "span" as you call it. | ||
| Marcoattici (Marcoattici) New member Username: Marcoattici Post Number: 10 Registered: 06-2012 |
just a question: if ours rafters are placed at a distance of 2 feet and 4 inches one to the others and a our deck, made out of kel wood its around one inch and a quorter do you think it'll bend under a load of 12 x 24 inches stones of 6-8 mm tickness?? i mean in case of bending will it be dangerous for the life of the whole roof | ||
| Branden_wilson (Branden_wilson) Senior Member Username: Branden_wilson Post Number: 125 Registered: 03-2008 |
thank you for sharing! it's wonderful to see the beautiful things that can only be produced in a free market. REAL SLATER | ||
| Lazeyjack (Lazeyjack) Senior Member Username: Lazeyjack Post Number: 61 Registered: 04-2012 |
myself I used screws, square drives simply cos the slate was thin and old in the case of repair you would need some long fine toothed hacksaw blade with a custom build handle to saw through the screws see my post somewheres on ply, i use ply cos there is no solid timber here, but, you need to paint it, with a quality epoxy, to a film thickness off 200 microns best rgds Stuart | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 130 Registered: 01-2012 |
you dont double nail through the slate the cheek nail goes where the slates butt together | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 129 Registered: 01-2012 |
cheek nail every third course like double nail it helps to stop the slates slewing | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 128 Registered: 01-2012 |
id use 50mm copper clouts screws could make maintenance annoying | ||
| Marcoattici (Marcoattici) New member Username: Marcoattici Post Number: 8 Registered: 06-2012 |
thanks Scottishslater. we were also thinking about screws. what would you suggest us | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 127 Registered: 01-2012 |
I like the nailing Marcoattici Scottish style for easy maintenance | ||
| Marcoattici (Marcoattici) New member Username: Marcoattici Post Number: 7 Registered: 06-2012 |
here a rough sketch of what we did  what do think about it? the pitch was about 5:12 any suggestion for the next one | ||
| Marcoattici (Marcoattici) New member Username: Marcoattici Post Number: 6 Registered: 06-2012 |
in Spain they call open ended or open slating in Jenkins bibles | ||
| Marcoattici (Marcoattici) New member Username: Marcoattici Post Number: 5 Registered: 06-2012 |
actually we have done it just because it's the tipical design of the state from where we got the slate, Himachial north India, besides the ventilation effect. as u can se below they have 2 different ways of laying stones one is single line   and the other one is double line  we have reduced the gap to 2" - 3" inches.. they have normally 5" .- 6" with the same size of stone of 10" - 20". we have also increased the headlap to 3" - 5" | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 846 Registered: 01-2009 |
I guess a good roof is one that doesn't leak. My question is why did you space the slates so far apart on that roof? I have seen a spec where that was done on a barn to generate ventilation through the spaced decking, but I have not seen it very often on a regular house roof. | ||
| Marcoattici (Marcoattici) New member Username: Marcoattici Post Number: 4 Registered: 06-2012 |
from the first pic to the following that we did last year.. we did ourselves from our experience.. i'll share other details later on.. we are trying to improve for the second big roof that we are going to do after the monsoon.     | ||
| Lazeyjack (Lazeyjack) Senior Member Username: Lazeyjack Post Number: 54 Registered: 04-2012 |
Mate I too have seen rooves in Italy 10 degree pitch with stone flats heaped on em, eventually the rafters croak it and the stones end up in bed with the owners In Montana now having come through all the Eastern states, not much slate on the journey tho some really interesting turrets all done or redone in ashfelt best rgds Stuart | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 843 Registered: 01-2009 |
Kind of like fish scales on a fish. Also a bit of the same thought process as the German method. As long as it sheds water, it is a good roof. Awful flat for a stone roof though. | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 120 Registered: 01-2012 |
am just used to trying to make everything square and true just looks unusual to me | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 840 Registered: 01-2009 |
Scottish, I think that the mortar is more a "filler" than anything else there. It is porous for sure, but it is all covered too. Those "slates" are more like flat rocks that they would make patios from than slates, but I am sure they would work. Just a lot more work. I have seen pictures of roofs in Italy where they use larger thicker rocks for the roofing. They are laid with about a triple headlap and each is drilled with a hammer drill and anchored to a purlon. That is what it reminds me of anyway. That would take a long time to do that kind of roofing. | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 113 Registered: 01-2012 |
that roof would only be as good as the cement under it one bad batch and your roofs goosed also cement is a porous material | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 112 Registered: 01-2012 |
slating in that picture looks rough as a badgers arse | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 837 Registered: 01-2009 |
That picture is from a point on the roof where they are roofing it. You can see the wet mortar at the tops of the rocks on the roof. As you say, it is quite flat too. If you are tearing that all off and going to install slate and they are in fact 12 x 24 inches, the normal exposure would be 10 1/2 inches. As Scottish slater says, you should use about 9 1/2 to 10 inches as an exposure for that low a pitch. 10 inches will give you a 4 inch headlap and 9 1/2 would give you a 5 inch headlap. Lay a few out and see where the nails holes are punched to see how much you can shrink them down. One other thing that comes to my mind would be to ,leave the plywood on the roof and just install the felt over that. Then, instead of fully decking the roof with 1 x lumber, use a 1 x 4 and install them vertically over the rafters, and then install 1 x 6's horizontally over them on 10 inch centers, so that the center of the 1 x 6's are centered on your nailing line. That is called "counter battening" and it allows for a continuous flow of air beneath the roof and it will also protect the felt from the heat and sun. It should last a long time and will also make your house cooler by moving the air all the time. You will not be using any more lumber either, which is a great thing. I don't know much about those woods you speak of so I can't advise you on them. Are they hard woods? If they are hard woods and they are dry, you are going to have a heck of a time driving nails into them. if they are green it will be easier, and that would be another reason to install the counter-battens as it will let them dry naturally. Good luck. | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 92 Registered: 01-2012 |
mark up roof with your proposed gauge all way to ridge then divide the the distance by the amount of courses youve marked up | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 91 Registered: 01-2012 |
headlaps same all way up if its low pitch give it about 4 inch | ||
| Scottishslater (Scottishslater) Senior Member Username: Scottishslater Post Number: 90 Registered: 01-2012 |
clout nails whats the name of those slate there using | ||
| Marcoattici (Marcoattici) New member Username: Marcoattici Post Number: 3 Registered: 06-2012 |
thanks old_school, actually it's this blue pine : http://en.wikipedia.org/wiki/Pinus_wallichiana. would be ok? to install the new boards right over the existing plywood it seems to be a very good idea we'll discuss it and we'll let you know. do you think or have you any experience that the eucaliptus wood could be the an other option? the slates are 12"x24" how much should be the headlap for the lower deck compare to the upper deck? and for the installation Would you use nails or screws of which kind? sorry to make so many questions but the history of this roof has started already few years back and we are trying, after reading J.J.'s book, to do less mistake as possible here is a picture from where we have started  thanks again | ||
| Old_school (Old_school) Senior Member Username: Old_school Post Number: 833 Registered: 01-2009 |
Marcoattici, are you saying that you have an option for "blue spruce"? If it is spruce, I am sure it would do just fine. I would be hesitant to install slates on that low of a pitch though. It will work mind you, but that is about as law a pitch as you would want to install slate on. Increase the headlap if you do. One thing to consider is that many people would consider walking on a 4 / 12 pitch roof and they tend to stay off from a 8 / 12 or steeper. I am sure you will find that if and when they do walk on it, they will end up breaking slates. Another thing you may consider is to just install the new boards right over the existing plywood if you have installed it already. It would not hurt anything and it would be less labor and super strong. Just a thought. | ||
| Marcoattici (Marcoattici) New member Username: Marcoattici Post Number: 2 Registered: 06-2012 |
thanks Catfeesh. have you any info about which wood could be the best choice for deck? | ||
| Catfeesh (Catfeesh) Junior Member Username: Catfeesh Post Number: 18 Registered: 12-2011 |
I'm not an expert, but have done a lot of reading. Joe recommends 1" thick lumber. Wikipedia says Red gum is used for rot resistant applications like fence posts, so it should last a long time on a roof. If it's dry, you may want to leave a small gap between boards to permit some expansion. There seems to be some debate on nail length, this article contains an explanation for why nails should not punch through the deck. http://www.traditionalroofing.com/TR5_readers_write.html | ||
| Marcoattici (Marcoattici) New member Username: Marcoattici Post Number: 1 Registered: 06-2012 |
Hi, we have started to build a roof with a slop of 3,5:12 on one side and 4.25:12 on the other side. we made a decking out of blu pine tree and then we decided to rise it up with the help of bidings to increase the slop till 4:12 and 5:12. at the present moment we put up plywood on the final decking. reading the forum we have been convinced to change the plywood with an other wood.. what do you think about eucaliptus (red gum wood)? somebody says that it's moving a lot. if it's good wich tickness will you suggest? if not, could the blu pine tree be an option for decking? or which other wood? going trough the web site we have found that you suggest nails 1 inch long plus two times the tickness of the slates. must the nails come out from the bottom side of the deck? if the slates are 7mm and the deck is 3/4 inch how long the nails shoud be? thank for helping |
