INSTALLING RAFTER TIES | More spread than a tub of Marge!

good afternoon welcome to the restoration  station my name is pete and it's thursday   the 25th of march i want to say 2021 this video  is about rafter ties oh yes how exciting you can   see this part of the building that i'm in has  no rafter ties uh so i'm going to be adding some   in and i'm going to be talking about the reasons  why and how i'm going to be doing it hopefully by   the end what i'm going to have is some exposed  rafter ties which will look quite cool now i'm   not going to divulge my plans for this part of the  building i'm still in consultation with the uh the   architectural drawer man uh building control and  also the planning department so while i'm waiting   for all of that sort of thing to take place i do  need to make sure that i'm getting this part of   the building structurally stable in my first  video i did a walk around the building and i   showed you some of the issues that this is having  over the last 150 years is the center of the roof   has begun to sag along the ridge in the middle  i'll show you more about that in the middle in   in a minute without the rafter ties that's all  the roof is it's just two sides of a triangle   and you need the base to tie it together so the  forces are acting outwards on these walls and the   walls are actually bowing because of that there  is cracking in the mortar as well on either side   more on this side because it's above the window  and also because of some other structural issues   further down the walls so there's a wooden  lintel that's a bit old it's a bit rotten   there's some brick work which is quite uh degraded  and and you've almost got a sort of subsidence   issue or a settlement issue halfway up the  building the first job to get all of this   sorted out is to get the roof stable so that it's  not acting outwards anymore with the rafter tires   on it'll then be held firmly in place the weight  will then be getting transferred down through   the walls vertically now i've had a word with  my structural engineer he's confirmed that i   don't need to have any calculations done  which is very good so i suggested to him   a certain thickness of timber a certain grade of  timber which i'll talk about in a minute and he   said yeah your ideas are about right and that's  great news because without needing calculations   it means i don't have to wait sort of four or  five weeks to get these things approved before   i can then stabilize the structure it's something  that needs doing pretty urgently now a rafter tie   to get technical can't go any higher than a third  of the way up the rafter because then it starts to   lose its effectiveness really and it then starts  becoming a collar tie which is something else   entirely and something i'm not going to talk  about in this video so a third of the way up   these rafters four timbers going across the timber  that i'm using it is four by two inch timber so   two inches thick four inches deep c24 grade  timber as opposed to c16 and the difference   there is c24 is a slower grown denser wood  with less imperfections so that means that   it's more suitable for structural applications  and also because these are going to be exposed   less imperfections in the wood mean that it should  look nicer as well and i may well paint or stain   the wood later on down the line i didn't want too  many timbers exposed because otherwise it will   it might look a little bit overkill but obviously  i need to have enough to do the job right here   we are outside and you can see this part of the  building that i've just been talking to you from   the ridge is sagging quite noticeably compared  to the rest of the building which does have   rafter ties and if we move over here look at the  building end on more evidence the wall is bowing   outwards but the gutter is a really good indicator  of that you know there's a there's a big bow in it   and it's exactly the same on the other side of  the building i won't bother showing you that now   but uh you can just take my word for it i'm not  lying to you there are also above this window which you may be able to see in the mortar just  up there and also under the guttering there are   quite a few loose bricks where the guttering  is being pushed away from the wall outwards   the fixing points are actually now dragging  bricks with it because the middle is wider   than the ends and so where it's attached at the  ends the bricks are being pulled out as well so   that all needs to be dealt with i will talk about  how i deal with that cracking in a separate video   so what we'll do is we'll go back up and i will  talk about the problems on the inside and you   can see the cracking is apparent above this lintel  here where the walls are being pushed outwards if   i show you along the wall plate here which is  a bit of timber that sits on top of the walls   you can see that that's but hang up  hang on a minute hang on what is this oh it's like a like an old pair of witch's  knickers or something my resident witch   leaving her underwear around the place hideous  right so now you can hopefully see that the wall   plate is bowing and it also appears to be rolling  outwards a little bit as well as a result of the   forces from the rafters pushing down and out on it  as i said i'm going to talk about how i remedy the   cracks but before i start taking out any mortar to  do that and potentially weaken or disrupt the wall   i want to stabilize the roof first before i start  tackling that so there's an order of works now i   want to show you on this side as well this wall  plate it's quite obvious that it's moved back   by about an inch or so so about the first section  of my index finger this wall plate was probably   built flush with these bricks originally  but now as a result of being pushed outwards   it's obviously shifted quite a bit it's not helped  by the fact that in the middle of this wall plate there is an articulation   where the r uh where the wall plate has  been joined there's another one here and there's one over here as well and that means  that instead of you know where one single piece   of wood may resist the movement a bit more  these joins have obviously allowed it to move   uh to a greater or lesser extent in in places  so another reason i've decided to have four   rafter ties in here is because where the  wall plate is joined i can have a rafter   tire on either side of the joint and that will  definitely belt and braces hold it in position   obviously i've had to consider ceiling  heights even though these are going to   be exposed you can't have them too low but what  i've figured out what what is quite fortunate   is that at 70 centimeters up this rafter it means  that i'm going to have somewhere in the region of   2 meters 20 ceiling height okay so now i'm  going to start installing the rafter ties   the first thing that i've done is i've created  a simple roof angle pitch finder if you like it's two pieces of timber bolted together with  one screw initially and then what i've done is put   my spirit level on the bottom held it up to the roof pitch  using the spirit level to find   level you then move the top timber into  place because it pivots on the single screw   when you have found the angle and the bottom is  level you then lock it into place with a second   screw and that then is your roof angle you know  this bottom timber is level when this top timber   is in line with the roof having  marked this 70 centimeter point   knowing that that's my center take the sharp  corner of this metal ruler and because the timbers   are four inches thick i know that the bottom edge  is going to be two inches below that center point   but it's really difficult to mark anywhere in  thin air the corner of this ruler into my 70   centimeter point and i can see the two inch mark  below that i'll then put my roof angle finder   up against it run it down until the bottom edge  which i know is level is on the two inch mark and   then i just follow that bottom straight edge that  bottom level edge along until i get to the rafter   i mark it off with a pencil here and then follow  that line across and i now know when i get to the   end of the rafter here that is the full level  bottom edge of that rafter and i of the rafter   tie and i put a screw in there knowing that that  is my furthest measuring point what i then do is take my chalk line which i've hung over that  screw over to the rafter on the opposite side i get up here with my spirit level  pull the chalk line taut and when   the spirit level is level and the chalk  line is up against the rafter on this side   once that's all lined up and level i then put a  screw or mark at the far end of the chalk line   on that rafter and then i know that is my furthest  point edge to edge of the bottom of the rafter tie   so i'll then go outside cut the timber off square  at that longest length and then what i'll do is using these basic roof pitch angle  finders and i've made one for both sides   and i'll have to do this custom for each rafter  tie that i install i will then transfer onto the   square cut rafter tie these angles  cut them off and then offer them up   and provided that everything fits properly  i'll then put a single screw screw   through either end to hold it in place drill  two 10 mil wood drill bit holes through both   the rafter and the rafter tie and then install two  stainless steel coach bolts other either end it's   it's gonna work but it's just oh do you know when  i said at the beginning i'm not a professional   builder you're gonna have to take what i do  with a pinch of salt this is a prime example so right so i thought i'd just show you  above the wall plate on this side as well   and oh my word the list of problems is as long as  my arm and keeps growing so you can see the ends   of these rafters are sort of there's an air gap  underneath them they're supposed to be supported   by this outer course of bricks where the wall  plate is pushing outwards the bricks are being   pushed outwards as well and where the mortars  failed they are obviously sinking down a bit as   well so that's leaving the rafter ends unsupported  so they're half on the wall plate and they're half   on the bricks but they're actually only half  on the wall plate now um so i will get these   bricks re-bedded i'll bring them back up under the  ends of the rafters so that there's no gap here   and that will then provide more support and it  will also with embedded in properly stop the wall   plate moving outwards as well and the rafter tires  are in and not a moment too soon either because   they're apparently forecasting 40 mile an hour  winds tonight so uh hopefully the reef is still   here in the morning when i wake up what i'm going  to do is show you around quickly apologies if the   light isn't great there's no electric lighting  up here i'm using my halogen work light my led   light to sort of show you around and it's blinding  me all i talk to you so hopefully you'll be able   to see what's been going on so there are three  rafter ties looking at it from this angle and if   i walk over here you'll see there's the fourth  rafter tie and the way that they're attached   is using two stainless steel 10 millimeters 10 of  them 10 millimeter bolts done up rather tightly   and held very securely in place now i did have  a bit of an issue a couple of times with hitting   nails that have been used to drive the battens and  attach them to the rafters from the roof side from   the outside um so i don't think it's going to make  a huge amount of difference but it's not ideal   to have drilled sort of an extra hole next to my  bolt hole but there's nothing i can do about it   and it's a bit of a guessing game it's just one  of those things but this timber is very strong   the roof uh rafters are sound so it should make  a noticeable difference in about a hundred years   when you come back and look and it hasn't moved  anymore okay so thanks very much indeed for   watching if you want to know what i'm doing with  this room going forward please do subscribe hit   the bell icon like any questions or comments in  the section below and in my next video i'm going   to be talking about how i deal with where the  tarmac road leading up to the church next door   has been built against the damp proof course of  this house so see you in my next video take care if i never hear the word rafter or  rafter tie again it'll be too soon

Channel: The Restoration Station

Views: 12,179

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Id: h9g5L0SkJbs

Length: 15min 28sec (928 seconds)

Published: Tue Mar 30 2021