1st Time Renovation Questions - with Photos - Please Help :)

[ldogg]

Hi everyone!

Newly registered on the forum but have been a silent watcher from the sidelines for some time and am hoping to get some help and advice

I am in the process of renovating my first house and have some questions about the rerendering/plastering after DPC injection.

The house is 1930's semi, and strangely was demolished prior to this, with the old original bricks used internally and new facing bricks used on the external leaf, these are different sized bricks and mean the mortar bed joints do not line up. The walls may aswell be solid as the cavity is basically non-existent and bridged all over from what I can see.

There is a dpc present on the external leaf although is below ground for the majority of the perimeter of the house due to pavements being built up over the years etc and there is no way to reduce this level. The house appears to be built straight on the ground and rising damp was visible in a few of the walls.

I have removed plasterwork to a height of 1200mm or 500mm above the rising damp marks and injected Dryzone cream from the inside and outside into the mortar joints.

I have used KA Tanking slurry on external walls and also fully tanked the two chimney breasts following advice gathered online and from a damp 'specialist' along with cutting out holes ready to put vents on.

I am wanting to have the whole house replastered, along with new kitchen etc. Some questions I have are as follows:

- The north facing gable wall was very cold to the touch with condensation noticeable, I have removed everything on this wall back to brick and would like some advice on whether to have it rerendered with sand/cement, or I have heard that the use of Thistle Dri-Coat can be used in these situations also? I understand that where the plaster has been removed for the DPC injection, I should rerender the walls downstairs incorporating a salt inhibitor (SBR?) in the first coat as well as sealing the wall with this?, or should I use the Thistle Dri-Coat?

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• ldogg
• 27 Feb 2013
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• ldogg
• 27 Feb 2013
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- Did I need to tank the entire chimney breast up to the ceiling? Also I injected this with dryzone but not sure I needed to do this either?

Tanked chimney

• ldogg
• 27 Feb 2013
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did I need to go to the ceiling?

- The open chimney I am wanting to have plastered and have had a light fitted in the soffit, how would be the best way to do this, I have done the first layer of tanking, if I fix wood to it and board the soffit wont I ruin the integrity of the tanking system?

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• ldogg
• 27 Feb 2013
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- Some of the reveals I have made up using board adhesive to fix plasterboard into them, although I have now thought I maybe should have had the renderer form these to avoid the damp spots coming through?

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• ldogg
• 27 Feb 2013
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- One of the windows is showing the plaster beads rusting which is coming through to the plaster slightly, do I need to remove these or can I put the plaster skim beads over as they are?

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• ldogg
• 27 Feb 2013
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• ldogg
• 27 Feb 2013
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- Do I need to remove wooden plasterbeads or can these be left in and new metal beads fixed ontop?

- I am leaving the existing wooden window lintels in, but have removed the plaster around these where cracks are present, I have started to fix metal mesh to these crack with plugs, screws and washers but is taking me a while. Would masonry nails be okay for this or am I wasting my time and will they just crack again anyway?

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• ldogg
• 27 Feb 2013
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Dryzone injected and tanking applied over

• ldogg
• 27 Feb 2013
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- I have boarded over an old alcove in the room which was where the old back door or window used to be years ago, should I use mesh on the wall to prevent any cracking when it gets rendered? You can see the dark shading which is where I presume the ground is wetter and the tanking is working?

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• ldogg
• 27 Feb 2013
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- Do I need to render underneath the stairs where I have injected the dryzone and tanked the wall? Or should I just brick back up the wall?

Understairs DPC/Tanking

• ldogg
• 27 Feb 2013
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Do I need to rerender under here or brick the wall back up?

Very sorry for the all the amateur questions but just want to get it done right and not have to redo it again in the future. All comments and critism would be much appreciated!

Thanks in advance!
Liam

 

[dann09]

Why didn't you come on here before doing anything?

To any other silent watchers, do come and ask questions before any work starts.
There are no stupid or amateur questions - just questions.

1. Do you have any written Surveyor, or Damp and Timber inspection reports?

2. Have you opened up the cavity and examined between the walls - 1930's houses constructed under Blg Regs all had cavities and ties.
Is the exterior rendered? Or, what state is the pointing in? Pics please?

3. Have you examined the exposed joist tails? Do your joists stop short of the damp wall?
Describe the u/floor venting airbricks, number and positions please. Extn. pics.

4. Injecting an external skin in a cavity wall is useless, and the internal injection should, if possible, go under the joist seats.
You should, perhaps, have a further look for an internal DPC.

5. If you have a blocked cavity, and high external ground levels, then your tanking effort is too low, but i dont know as i would raise it. Maybe a traditional render to 1m would suffice.
Thistle Dri-Coat and Thistle Board Finish will both work. But dont use additives with them.

6. KA Tanking Slurry will give a hard surface and might be a future cause of excessive condensation.

7. Did you remove all soot from the fire back prior to "tanking"?
Did you sweep the flue(s) and inspect the stack terminal?

8. Have you examined the wood lintel bearing ends?
Replace any rusting mesh/bead.
There should be cavity trays above the RSJ and wood lintels - but it's a bit late now. However, moisture might ingress from above.

9. Remove whatever you've installed at the w/f reveals - thing is, that there wont be reveal, vertical cavity closers to stop bridging damp. Perhaps examine the external pointing of the W/F? More pics.

10. A couple of tips: dont perch tools or objects on ledges or ladders, leave the hand saw teeth up on a hard surface, and remove all nails as boards are lifted. Remove rads and any clutter away from the work area/room.

Note: You might be best advised in getting an on-site view from an Independent Damp and Timber Surveyor.

 

[ldogg]

Hi Dan,

Sorry for the delay in responding after you took the time to reply.

I had an independant surveyor round, and confirmed the rising damp issues, fortunately the floor is sat on sleeper walls which are not touching the internal leaf of brickwork and there is some kind of dpc present between the brick sleeper walls and floor joists, it is like a felt? It seems to have stood the test of time as the floor is solid fortunately. The airbricks are functioning at the front of the house where the external ground level is at its lowest, but as you move around the house the levels rise and the airbricks are covered from the tarmac pavements. I should note that this is where the floors are concrete so I beleive less of an issue.

I have included a photo showing the wall construction, a cavity is present but no ties and as you can see is bridged with snots of mortar etc.

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• ldogg
• 28 Mar 2013
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Part is rendered, part is brick, the brickwork could do with repointing, I have no picture to show this currently unfortunately.

Chimney flue was swepgt before tanking, and as the tanking seems to have debonded i wirebrushed it and applied a sand/cement/sbr prior to retanking, this has helped although the tanking has debonded again in locations, I have included a photo of this.

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• ldogg
• 28 Mar 2013
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• ldogg
• 28 Mar 2013
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I am contemplating building a 100mm skin to line the inside of the fireplace now and render onto that, would i need to put a dpc under this skin? Also I am unsure what I should do in the 'bit' where the fire would have been trsaditionally, would i need to dig this out, put a membrane down and concrete? Then finish with some slabs of some kind ontop?

I have included some more photos of the windows, what would you suggest I did to form these? As you can see there is quite a lot to build up to bring it out to the window, how should I do this?

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• ldogg
• 28 Mar 2013
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• ldogg
• 28 Mar 2013
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• 28 Mar 2013
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• ldogg
• 28 Mar 2013
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Thankyou for all your tips and help!

Liam