Gavin’s timber frame thread

[Onoff]

3 minutes ago, gavztheouch said:

Unfortunately the joiners have used half the amount of foaming glue needed so the glue has not sealed the boards and already after a couple of days the edges have swollen.

 

Can you plane the swollen bit level?

[gavztheouch]

4 minutes ago, Onoff said:

 

Can you plane the swollen bit level?

Probably can do that. until I put a straight edge across its hard to see how bad it is now. If it doesn’t get much worse then it will be fine for carpets. Might need to plane down the bathrooms if they are tilled or vinyl.

[Alan Ambrose]

You should be able to plane it quite easily, but the edges will be even more vulnerable I think. Possible to cover them with something at least temporarily waterproof? Some kind of tape maybe?

Edited October 7 by Alan Ambrose

[Russell griffiths]

Mix up a Solution of linseed oil and turps, brush it all over the joins and let it soak in.
 

this used to be the way before the egger stuff was invented. 

[gavztheouch]

On 24/09/2024 at 22:36, Iceverge said:

 

I'd be cautious about this. If any moisture was to run down between the woodfiber and membrane it would be directed into the house. I'd cut the DPM  back flush with the outsider of the sole plate. 

 

 

It would be difficult to build if you did this. You'd need to be putting the membrane up as you did the woodfiber. 

 

In general think always about allowing water to down and out. This might potentially create a pocket that would trap water against the membrane. 

 

Something else to consider is that the membrane and cladding may need to be replaced, it might be 100 years but it may need to happen. Ideally for the sake of whoever has to do this it should be removable without damaging the woodfiber. 

@Iceverge Im about to start adding the external wood fibre to my build. Im interested to hear if you still think stapling the dpm to the wall is a bad idea? I should clarify the dpm will be folded up against the racking board which is behind the wood fibre so it would need to get in between the wood fibre and the racking board which I guess would be possible. To prevent it diverting any water towards the sole plate I was planning on adding some pro clima tape to hold it against the racking board making it even more unlikely to divert water into the wall.

 

If I could go back in time I would have maybe stapled it against the studs as this would be very unlikely to have water running down the studs. I didn't do this as the nails for the racking board would go through the dpm.

[gavztheouch]

On 24/09/2024 at 13:31, Iceverge said:

 

 

Very Interesting build. 

 

I would avoid multi tooling anything. It's too slow and getting a very consistent cut would require too much attention. 

 

This would be my solution. 

 

Cut say a 300 mm strip of proclima and staple it to the racking board as shown in orange. 

 

Then run the breather membrane over the top as shown in blue to below the level of the orange. 

 

Tape the blue to the isoquick with an appropriate tape and primer. 

 

 

This will be a safe design if the tape fails, or the external membrane. 

 

 

However getting the external membrane and tape right is your primary objective..

I really like this idea but now I'm not sure I should do it. My concern is if any water finds it way to the bottom of the wall, the external membrane is trapping the water from getting out as it is taped to the upstand. There is however a possible path out as the gaps between the isoquick as quite large, some almost 10mm. These could work pretty nice as drains. If I put the tape marked in orange this will bridge over the gaps and stop the water.

 

My next though was keeping these drains clear. I think I might have to prime the cut edge of the wood fibre board and run a length of pro clima 100mm wide vana tape over the edge to stop all the fluffy bits of wood coming off and washing down into the drain. 

[Iceverge]

On 02/11/2024 at 04:47, gavztheouch said:

@Iceverge Im about to start adding the external wood fibre to my build. Im interested to hear if you still think stapling the dpm to the wall is a bad idea? I should clarify the dpm will be folded up against the racking board which is behind the wood fibre so it would need to get in between the wood fibre and the racking board which I guess would be possible. To prevent it diverting any water towards the sole plate I was planning on adding some pro clima tape to hold it against the racking board making it even more unlikely to divert water into the wall.

 

If I could go back in time I would have maybe stapled it against the studs as this would be very unlikely to have water running down the studs. I didn't do this as the nails for the racking board would go through the dpm.

 

If you tape it it should be fine. However the effort in doing so might not be rewarded in any extra resilience over just cutting it off.

 

As a general principal I would very much lean towards a simpler build is better. Extra membranes and tapes goes against this philosophy. 

 

 

[Iceverge]

On 02/11/2024 at 04:57, gavztheouch said:

I really like this idea but now I'm not sure I should do it. My concern is if any water finds it way to the bottom of the wall, the external membrane is trapping the water from getting out as it is taped to the upstand. There is however a possible path out as the gaps between the isoquick as quite large, some almost 10mm. These could work pretty nice as drains. If I put the tape marked in orange this will bridge over the gaps and stop the water.

 

My next though was keeping these drains clear. I think I might have to prime the cut edge of the wood fibre board and run a length of pro clima 100mm wide vana tape over the edge to stop all the fluffy bits of wood coming off and washing down into the drain. 

 

Ok, I see what you are saying. 

 

The priority risk is wind driven rain making it's way in between the eps foundation and the woodfiber ultimately damage the sole plate and sheathing so I would be keen to keep a mechanically robust detail in place here to stop that happening. 

 

However I would argue that if your window and door detailing is done to a good standard above this, then you lose the benefits of a completely taped wind tight layer unless you secure the membrane to the foundation. 

[gavztheouch]

23 hours ago, Iceverge said:

 

Ok, I see what you are saying. 

 

The priority risk is wind driven rain making it's way in between the eps foundation and the woodfiber ultimately damage the sole plate and sheathing so I would be keen to keep a mechanically robust detail in place here to stop that happening. 

 

However I would argue that if your window and door detailing is done to a good standard above this, then you lose the benefits of a completely taped wind tight layer unless you secure the membrane to the foundation. 

Yes I will be tapping the membrane to the foundation upstand. The folded up dpm or any extra bits of tape and membrane were meant to be extra barriers. Now that I have thought about it more I will revert back to the original detail of using just the membrane to stop the water getting through to the sole plate. Like you say keep it simple and try and do it well. Maybe I will monitor some choice points of the wall in times of windy wet weather to see if I can see any water getting through. An ideal solution would be a wire or some type of detector that could detect water at the sole plate. Then we would know to fix the membranes/window taping 

[gavztheouch]

Looking for some opinions on my roof. I have a 18mm plywood ventilated deck for my standing seam roof. It sits on top of the basic roof joists and osb.

 

the deck is 18mm plywood sitting on top of 50x50mm battens. 
 

Today we installed the 50x50mm battens. We used 100mm spax stainless steel screws to hold the battens down. I was worried about the 600mm centers not being accurate enough to make sure we were screwing into the joists ( I measured them drifting out with my 30m tape over the whole length of the roof. The joiner assured me not one screw will miss the rafters. Over the first ten joists this was mostly true as I didn’t spot many not hitting their target. I felt assured and went off and did something else. When I returned at night with my head torch I noticed a few screws that did not go into the joist. As I walked to the far end of the roof it got a lot worse, I counted 103 screws missing the rafters out of 300 so about 1/3. Not to mention the ones you can’t see that will be just under the surface with not much holding force. Some rafters have every screw on the batten missing the rafters. My intuition say the engineer will have over specked and this will most likely be ok as it is. However I am not very happy that things like this keep happening. The only way of fixing it would be to have someone inside spotting for someone on the roof to call out which screws to remove and rescrew. This will make a lot of hole in the membrane but I have come to relise this first membrane should hopefully never see water, however it is still annoying. I also don’t think they will fix it or I will need to pay them to fix it. 
 

I also don’t like all these screws poking out as it will make getting a good fit for my wood fibre insulation difficult.
 

Should I be annoyed, what would you do?

[saveasteading]

Yes be annoyed. If they miss at 600cc, then there is 1200 between fixing. That's too far.

Regardless of anyone's hunch in it  your Engineer has said 600, so that should be done.

2 hours ago, gavztheouch said:

My intuition say the engineer will have over specked 

They may have gone to the next screw size up, but don't play with centres or miss any out.

[SteamyTea]

I have corrected your handedness for you, you be OK now.

 

[gavztheouch]

https://youtu.be/uZf9aAsytm4?si=TO_7B4VJdSwwK2bB

 

I have a question about my parapet walls and thermal bridges

 

I think as a compromise I might just use one 245mm by 45mm for the upstand and cover it with 60mm insulation on the outside to keep it warmer

Edited December 7 by gavztheouch

[gavztheouch]

Hi everyone, Im looking for some ideas and opinions on my flat roof design by my architect. I am a bit worried about the use of sealant as a primary waterproofing layer on my new build roof. Here is a walkthrough of the design and how to build/sequence the detail.

 

Step one:  The green coloured roof in the image is a layer of osb attached to the rafters, it is covered in a breather membrane. The purple part is firestone epdm formed inside the parapet, up the walls and down the other side of the parapet to form a little triangle web.

 

 

Step two: A ventilated deck is formed above the original osb roof and epdm. This layer is covered in another breather membrane. There is a plywood upstand running up the cheeks to form the standing seam upstand against.

 

 

Step Three: Standing seam Greencoat metal roofing material is added, note the upstand against the dormer cheeks.

 

 

Step four: A flash band tape is added to seal the standing seam metal roof against the dormer cheek membrane. The tape is called extoseal by proclima. 

 

 

Step five: Cladding battens are added.

 

 

Step Six: Add wooden cladding

 

 

Step Seven: Adding metal capping piece over parapet walls tight against metal roof

 

 

Step eight: Add sealant where the capping piece meets the roof.

 

 

My issue with the design is the reliance on sealant to waterproof the junction between the capping piece and metal roof. This will have the roof above pouring water onto this area and also wind driven rain will be blown back against it. I have 4 dormer windows so there will be 8 of these junctions. The architect did mention I could slip the capping piece under the standing seam. I think for that to be better it would need to be running up the roof with a suitable overlap to stop wind driven rain and capillary action. I think it would also need to flair out and become flat to be able to go under the roof which will be difficult with a steel capping piece. Also unless you lap the metal roof like slates in this area you will always need to seal certain edges with sealant.

 

I have a few ideas on how to better the design but I wanted to get some opinions on the design as it stands today. Would you do this detail on your new roof?

 

Cheers

Gavin

 

 

Edited Thursday at 07:48 by gavztheouch

[saveasteading]

You are correct. Flashband and sealant is more  for repairs than newbuild. 

You should be channeling the water away from the interface using metal flashings. These should underlap the cladding, say 100mm or more.

You do need sealant. It should be a tape of silicon that is screwed tight at the joint. It should be  a specific to cladding product that does not harden in time.