Leak under door?

Sorry realised I put this in wrong forum so asking again here…

I have a patio door on my recently built garage, and I noticed that the concrete floor inside became wet after the heavy rain last weekend.

The door sits in the single skin blockwork which is rendered but underneath the door was just left as exposed block. I suspect the builders haven’t lapped the DPM up under the door on the inside. Also they roughly filled the gap under the door where it sits on the block with foam which could let water seeping through the block in. They then covered this gap with a strip of plastic.

ive attached picture. Any suggestions to eliminate this problem would be appreciated?

At the moment I am thinking:

Remove plastic strip. Seal gap under door with sealant. Once dry cover this gap over to block with waterproof tape, then replace the the plastics strip with a much deeper plastic board as far down under ground as I can get to in order to divert water as far down from doorframe as possible. Hopefully this would reduce chances of it seeping up through the block

I am also concerned that there is no sill or step at the bottom of the doors to deflect water away.

could I retro fit something?

How does it drain?

I’m not sure, didn’t know they need to!

I’ll have a look tomorrow, what should I look for?

I’ve had a look and can see inside the frame there appears to be slots and on the front face holes, presumably for drainage.

you can also see on below pic an area where water was coming inside in the corner

Where to start oh dear. Those external holes have been drilled by the builder, I know this because they are too high up, they need to be as low down as possible so water doesn't collect in the internal chamber.

The second issue is is there already pre drilled face drainage holes done at the factory BEHIND that bit of plastic trim, I would suspect so seeing as there's no cill, if a cill was used then you'd have concealed drainage, no cill then face drainage, so if you are getting water pooling in the pvc frame when it drains away through the lower drainage holes now cloaked over any water could run backwards under the frame

It could also just be water wicking under the door or through the render and being no cavity to act as a break, in 30 years of fitting I always found damp patches on single skin walls, mainly cheap and cheerful porches

It could also be that a cill was ordered but not used for some reason so now the frame has concealed drainage as well as face drainage that the builders drilled in but any water will always now drain through the lower concealed drainage, if you've dropped a clanger and changed to face drain on site it's imperitive you block up the concealed drainage with silicone, maybe the haven't?

Thanks for replying

Would the concealed drainage you say to block up be the slots you can see in the bottom of the frame?

May be a silly question but how does the water get into the frame in the first place?

Do you think I should look at trying to retro fit a sill type drip bar along the frame to direct water away from the wall under the door?

It also hasn’t been sealed on the inside around the door or at the base, would that do anything?

Here is an illustration on how concealled and face drainage works

This is face drainage, the blue line is the route water takes as it drains away, note the hole coming out of the face needs to be as low as possible so as water can't build up marked in green, drilling higher up marked in red allows water to build up before it reaches the drian hole level, this could also allow water to seep past the welds in the corners before reaching the drain hole level, also note the drain slot doesn't go right down through the whole section like concealled drainage



This is concealled drainage, note that the hole is under the frame now(concealled) and the hole is drilled vertically upwards right through all the chambers.



If they have omitted the cill and drilled face drainage holes then its imperative to seal up the concealled hole(circled) otherwise water could follow the red line backwards, it can't drain forward because they've stuck a trim along the bottom, this trim either covers a lower (green) drainage hole hence they drilled one higher up but didn't really think about the implications OR its still got its original concealled drainage and again the trim piece is covering it, incidentally you never never ever have concealled drainage unless your using a cill, if the frame is sitting straight onto concrete like yours then it always has to be face drained, without taking your trim off its impossible to know what they've done, you may have both face and concealled drainage

To answer your question on how does water get in there, well as your doors open outwards rain water will seep past the gaskets along the top of the doors and drip into the threshold, thats normal for pvc and aluminium, it won't be lots maybe just half an egg cup of water, the drainage holes will easily deal with that

Thank you,

I will take that strip of trim off to see if I can see any more holes.

if I can’t am I going to have to get the door removed and a sill fitted?

I’ll try and ask the builders if they drilled those holes also

it'll only be stuck on with silicone and will peel off, really need to see if its hiding lower face drain holes, I suspect it is because the higher up ones aren't factory drill, they're just too high up. Cill's are 30mm tall as you can see in my pictures so there needs to be a 30mm gap above the door or 50/50 top and bottom, enough to fit a cill in, fingers crossed you have enough room, if not you can handsaw the ribs off the top of the frame, that'll get you 7mm

Sorry, just to be clear the door needs to come out unless there are holes behind the trim?

Yes if there are no holes behind that trim then it has had concealled drainage drilled which points to the doors being spec'd with a cill, maybe they were measured wrong or didn't include the cill in the overall height and there was no room left to use the cill so it was left out so yes if no face drainage holes then the doors need to come out and the concealled drainage sealed up because as of now you both types of drainage and the water is taking the one with least obstruction, in fact you have 3 if you include the extra holes drilled higher up.

Having said all this the water could well just be wicking through the concrete floor or single skin wall, that needs investigating just as much.

And some think window fitting is easy lol!